Chinese constellations

Traditional Chinese astronomy has a system of dividing the celestial sphere into asterisms or constellations, known as "officials" (Chinese "xīng guān").
The Chinese asterisms are generally smaller than the constellations of Hellenistic tradition.
The Song dynasty (13th-century) Suzhou planisphere shows a total of 283 asterisms, comprising a total of 1,565 individual stars.
The asterisms are divided into four groups, the Twenty-Eight Mansions (, "Èrshíbā Xiù") along the ecliptic, and the Three Enclosures of the northern sky.
The southern sky was added as a fifth group in the late Ming Dynasty based on European star charts, comprising an additional 23 asterisms.
The Three Enclosures (, "Sān Yuán") are centered on the North Celestial Pole and include those stars which could be seen year-round.
The Twenty-Eight Mansions form an ecliptic coordinate system used for those stars visible (from China) but not during the whole year, based on the movement of the moon over a lunar month.
History.
The Chinese system developed independently from the Greco-Roman system since at least the 5th century BC, although there may have been earlier mutual influence, suggested by parallels to ancient Babylonian astronomy.
The system of twenty-eight lunar mansions is very similar (although not identical) to the Indian "Nakshatra" system, and it is not currently known if there was mutual influence in the history of the Chinese and Indian systems.
The oldest extant Chinese star maps date to the Tang dynasty. Notable among them are the 8th-century "Treatise on Astrology of the Kaiyuan Era" and "Dunhuang Star Chart.
It contains collections of earlier Chinese astronomers (Shi Shen, Gan De and Wu Xian) as well as of Indian astronomy (which had reached China in the early centuries AD).
Gan De was a Warring States era (5th century BC) astronomer who according to the testimony of the Dunhuang Star Chart
enumerated 810 stars in 138 asterisms. The Dunhuang Star Chart itself has 1,585 stars grouped into 257 asterisms.
The number of asterisms, or of stars grouped into asterisms, never became fixed, but remained in the same order of magnitude (for the purpose of comparison, the star catalogue compiled by Ptolemy in the 2nd century had 1,022 stars in 48 constellations).
The 13th-century Suzhou star chart has 1,565 stars in 283 asterisms, the 14th-century Korean Cheonsang Yeolcha Bunyajido has 1,467 stars in 264 asterisms, and the celestial globe made by Flemish Jesuit Ferdinand Verbiest for the Kangxi Emperor in 1673 has 1,876 stars in 282 asterisms.
The southern sky was unknown to the ancient Chinese and is consequently not included in the traditional system. With European contact in the 16th century, Xu Guangqi , an astronomer of the late Ming Dynasty, introduced another 23 asterisms based on European star charts. The "Southern Sky" () asterisms are now also treated as part of the traditional Chinese system.
Terminology.
The Chinese word for "star, heavenly body" is "".
The character originally had a more complicated form: , a phono-semantic character () whose semantic portion, , originally depicting three twinkling stars (three instances of the "sun" radical ).
The modern Chinese term for "constellation", referring to those as defined by the IAU system, is ('). The older term (') is used only in describing constellations of the traditional system. The character means "public official" (hence the English translation "officials" for the Chinese asterisms), but it is historically a variant glyph of
"" "temple, palace", in origin a pictogram of a large building.
The generic term for "asterism" is ("", lit. "group of stars").
Three Enclosures.
The Three Enclosures are the Purple Forbidden enclosure (, "Zǐ Wēi Yuán"), the Supreme Palace enclosure (, "Tài Wēi Yuán") and the Heavenly Market enclosure (, "Tiān Shì Yuán").
The Purple Forbidden Enclosure occupies the northernmost area of the night sky. From the viewpoint of the ancient Chinese, the Purple Forbidden Enclosure lies in the middle of the sky and is circled by all the other stars.
It covers the Greek constellations Ursa Minor, Draco, Camelopardalis, Cepheus, Cassiopeia, Auriga, Boötes,
and parts of Ursa Major, Canes Venatici, Leo Minor, Hercules.
The Supreme Palace Enclosure covers the Greek constellations Virgo, Coma Berenices and Leo,
and parts of Canes Venatici, Ursa Major and Leo Minor.
The Heavenly Market Enclosure covers the Greek constellations Serpens, Ophiuchus, Aquila and Corona Borealis,
and parts of Hercules.
The Three Enclosures are each enclosed by two "wall" asterisms, designated "yuán" "low wall, fence; enclosure" (not to be confused with the lunar mansion ""Wall" ):
The Twenty-Eight Mansions.
The Twenty-Eight Mansions are grouped into Four Symbols, each associated with a compass direction and containing seven mansions. The names and determinative stars are:
The Southern Asterisms ().
The sky around the south celestial pole was unknown to ancient Chinese. Therefore, it was not included in the Three Enclosures and Twenty-Eight Mansions system. However, by the end of the Ming Dynasty, Xu Guangqi introduced another 23 asterisms based on the knowledge of European star charts. These asterisms were since incorporated into the traditional Chinese star maps.
The asterisms are :
Chinese star names.
Ancient Chinese astronomers designated names to the visible stars systematically, roughly more than one thousand years before Johann Bayer did it in a similar way. Basically, every star is assigned to an asterism. Then a number is given to the individual stars in this asterism. Therefore, a star is designated as "Asterism name" + "Number". The numbering of the stars in an asterism, however, is not based on the apparent magnitude of this star, but rather its position in the asterism. The Bayer system uses this Chinese method occasionally, most notably with the stars in the Big Dipper, which are all about the same magnitude; in turn, the stars of the Big Dipper, in Chinese, are numbered in Chinese astronomy in the same order as with the Bayer designations, with Dubhe first in both cases.
For example, Altair is named in Chinese. is the name of the asterism (literally the Drum at the River). is the number designation (two). Therefore, it literally means "the Second Star of the Drum at the River". (Bayer might have called Altair "Beta Tympani Flumine" if he had been cataloguing Chinese constellations.)
Some stars also have traditional names, often related to mythology or astrology. For example, Altair is more commonly known as or (the Star of the Cowherd) in Chinese, after the mythological story of the Cowherd and Weaver Girl.
These designations are still used in modern Chinese astronomy. All stars for which the traditional names are used in English are routinely translated by their traditional Chinese designations, rather than translations of their catalogue names.
By modern IAU constellation.
The following is a list of the 88 IAU constellations with the Chinese translation of their names.
Each linked article provides a list of the (traditional) Chinese names of the stars within each (modern) constellation.


LS Canis Majoris

LS Canis Majoris is an eclipsing binary star located around 1018 light years from Earth in the constellation Canis Major. The apparent magnitude ranges from 5.57 to 5.6. The component stars are blue-white giant stars of spectral types B2III or IV and B3III or IV respectively.


Upsilon Andromedae b

Upsilon Andromedae b (υ Andromedae b, abbreviated Upsilon And b, υ And b), formally named Saffar , is an extrasolar planet approximately 44 light-years away from the Sun in the constellation of Andromeda. The planet orbits the solar analog star, Upsilon Andromedae A, approximately every five days. Discovered in June 1996 by Geoffrey Marcy and R. Paul Butler, it was one of the first hot Jupiters to be discovered. It is also one of the first non-resolved planets to be detected directly. Upsilon Andromedae b is the innermost known planet in its planetary system.
In July 2014 the International Astronomical Union launched a process for giving proper names to certain exoplanets and their host stars. The process involved public nomination and voting for the new names. In December 2015, the IAU announced the winning name was Saffar for this planet. The winning name was submitted by the Vega Astronomy Club of Morocco and honours the 11th Century astronomer Ibn al-Saffar of Muslim Spain.
Discovery.
Upsilon Andromedae b was detected by the variations in its star's radial velocity caused by the planet's gravity. The variations were detected by making sensitive measurements of the Doppler shift of Upsilon Andromedae's spectrum. The planet's existence was announced in January 1997, together with 55 Cancri b and the planet orbiting Tau Boötis.
Like 51 Pegasi b, the first extrasolar planet discovered around a normal star, Upsilon Andromedae b orbits very close to its star, closer than Mercury does to our Sun. The planet takes 4.617 days to complete an orbit, with a semimajor axis of 0.0595 AU.
A limitation of the radial velocity method used to detect Upsilon Andromedae b is that only a lower limit on the mass can be found. The true mass may be much greater depending on the inclination of the orbit. A mass of and an inclination of 24° were later found using high-resolution spectroscopy.
Physical characteristics.
Given the planet's high mass, it is likely that Upsilon Andromedae b is a gas giant with no solid surface.
The Spitzer Space Telescope measured the planet temperature, and found that the difference between the two sides of Upsilon Andromedae b of about 1,400 degrees Celsius, ranging from minus 20 to 230 degrees to about 1,400 to 1,650 degrees Celsius. The temperature difference has led to speculation that Upsilon Andromedae b is tidal locked with the same side always facing Upsilon Andromedae A.
Sudarsky had, on the assumption that the planet is similar to Jupiter in composition and that its environment is close to chemical equilibrium, predicted Upsilon Andromedae b to have reflective clouds of silicates and iron in its upper atmosphere. The cloud deck instead absorbs the sun's radiation; between that and the hot, high pressure gas surrounding the mantle, exists a stratosphere of cooler gas. The outer shell of dark, opaque, hot cloud is assumed to consist of vanadium and titanium oxides, but other compounds like tholins cannot be ruled out yet.
The chemical elements in the atmosphere can be studied by finding their absorption lines in the thermal spectrum of the planet; given typical planet temperatures, the spectrum has its peak at infrared wavelengths. So far, only water vapor has been detected in this planet, while carbon monoxide and methane are still under the detection limit.
The planet is unlikely to have large moons, since tidal forces would either eject them from orbit or destroy them on short timescales compared to the age of the system.
The planet (with 51 Pegasi b) was deemed a candidate for direct imaging by Planetpol. Preliminary results from polarimetric studies indicate that the planet has predominately blue color, is 1.36 times as large and 0.74 times as massive as Jupiter, meaning that the mean density is 0.36g/cm3. It has a geometric albedo of 0.35 in visible light. Tidal heating models predict a similar mass for the planet.
Effect on the parent star.
Upsilon Andromedae b appears to be responsible for increased chromospheric activity on its parent star. Observations suggest that there is a "hot spot" on the star around 169° away from the sub-planetary point. This may be the result of interactions between the magnetic fields of the planet and the star. The mechanism may be similar to that responsible for the activity of RS Canum Venaticorum variable stars, or the interaction between Jupiter and its moon Io.


NGC 2573

NGC 2573 (also known as Polarissima Australis) is a barred spiral galaxy located in the constellation Octans, discovered in 1837 by John Herschel. It is the closest NGC object to the South Celestial Pole.


HAT-P-6

HAT-P-6 also named Sterrennacht is a star in the constellation Andromeda, located approximately 910 light years or 280 parsecs away from the Earth. It is an F-type star, implying that it is hotter and more massive than our Sun. The apparent magnitude of the star is +10.54, which means that it can only be visible through the telescope. The absolute magnitude of +3.36 is brighter than the Sun's +4.83, meaning that the star itself is brighter than the Sun. A search for a binary companion star using adaptive optics at the MMT Observatory turned out negative.
The name Sterrennacht (Starry Night) was selected in the NameExoWorlds held by the IAU by the Netherlands is a world-famous painting by Dutch grand master Van Gogh.
Planetary system.
The companion planet HAT-P-6b is a transiting planet discovered on October 15, 2007 by the HATNet Project. The planet's true mass is slightly more than Jupiter at only 5.7%, but the radius is 33% greater, making the planet's density of 0.45 g/cm3. Its large size compared to mass comes from the great amount of heat received from the nearby star that expands the planet's atmosphere, categorizing as "hot Jupiter". The orbital period is 3.852985 days and the distance from its star is 0.05235 AU. The inclination of the orbit with respect to the stellar rotation axis is roughly 166º.


Epsilon Librae

Epsilon Librae (ε Lib) is the Bayer designation for a binary star system in the zodiac constellation Libra. With an apparent visual magnitude of 4.922, it is bright enough to be seen with the naked eye. Based upon an annual parallax shift of 32.02 mas, it is located about 102 light years away from the Sun.
This is a single-lined spectroscopic binary star system. The pair orbit each other with a period of 226.9 days and an eccentricity of 0.66. The semimajor axis of their orbit is estimated to be 0.85 AU, or 85% of the distance from the Earth to the Sun. The primary, component A, has been catalogued with stellar classifications of F3 V and F5 IV, suggesting that it is an F-type star that either belongs to the main sequence or has evolved into a subgiant as the hydrogen at its core nears exhaustion.
The primary has an estimated 1.17 times the mass of the Sun and 1.5 times the Sun's radius. It is around 1.5 billion years old and is spinning with a projected rotational velocity of 10 km/s. The star radiates 9.3 times the solar luminosity from its outer atmosphere at an effective temperature of 6,552 K. The secondary, component B, has 41% of the Sun's mass.


Pi Mensae b

Pi Mensae b (π Men b, π Mensae b), also known as HD 39091 b, is an extrasolar planet approximately 59 light-years away in the constellation of Mensa. The planet was announced orbiting the yellow main-sequence star Pi Mensae in October 2001.
Detection and discovery.
On October 15, 2001, a team of astronomers including Jones, Butler, Tinney, Marcy, Penny, McCarthy, Carter, and Pourbaix announced the discovery of one of the most massive extrasolar planets that have yet been observed. It was discovered by the Anglo-Australian Planet Search team, using a Doppler spectrometer mounted on the Anglo-Australian Telescope.
Physical characteristics.
Pi Mensae b has a very eccentric orbit and takes 5.89 years to revolve around the star. The semi-major axis of the planet to the star is 3.38 AU while the semi-minor axis is 2.59 AU. This planet passes through the star's habitable zone at periastron (1.21 AU) while at apastron, it passes to beyond Jupiter-Sun distance (5.54 AU). The gravitational influence of this planet would disrupt the orbit of any potentially Earth-like planet.
Pi Mensae b is over ten times more massive than Jupiter, the most massive planet in our solar system. It will have 10 times the surface gravity of Jupiter alone and could be incandescent (glowing).
The Pi Mensae b was confirmed to be a brown dwarf with the accurate mass measurement in 2020.
The plane of orbit of Pi Mensae b is strongly inclined to equatorial plane of the star, with the misalignment equal to 24±4.1°.


Mu Capricorni

Mu Capricorni (μ Cap, μ Capricorni) is a solitary star in the southern constellation of Capricornus. Based upon an annual parallax shift of 37.57 mas as seen from the Earth, the star is located about 87 light years from the Sun. It is visible to the naked eye with an apparent visual magnitude of +5.081.
It is a yellow-white hued, F-type main sequence star with a stellar classification of F2 V. It is an estimated 1.6 billion years old and is spinning with a projected rotational velocity of 69 km/s. The star has 1.29 times the mass of the Sun and around 1.8 times the Sun's radius, with an effective temperature of 6,892 K.
In Chinese, (), meaning "Crying", refers to an asterism consisting of μ Capricorni and 38 Aquarii. Consequently, the Chinese name for μ Capricorni itself is (, .). From this Chinese name, the name Kuh has appeared.


UGC 4904

UGC 4904 is a barred spiral galaxy in the constellation Lynx, located about 77 million light-years from Earth. On October 20, 2004, a supernova impostor was observed by Japanese amateur astronomer Koichi Itagaki within the galaxy. This same star may have transitioned from a LBV star to a Wolf–Rayet star shortly before it was observed as blowing up as hypernova SN 2006jc on October 11, 2006.


Alpha Pegasi

Alpha Pegasi (α Pegasi, abbreviated Alpha Peg, α Peg), formally named Markab , is the third-brightest star in the constellation of Pegasus and one of the four stars in the asterism known as the Great Square of Pegasus.
Properties.
Alpha Pegasi has a stellar classification of A0 IV, indicating that it is an A-type subgiant star that has exhausted the hydrogen at its core and has evolved beyond the main sequence. Its spectrum has also been classified as B9V and B9.5III.
It is rotating rapidly, with a projected rotational velocity of 130 km/s giving a lower bound on the azimuthal velocity along the star's equator. The effective temperature of the photosphere is about 10,000 K and the star has expanded to nearly five times the radius of the Sun, emitting 165 times as much energy as the sun.
Nomenclature.
"α Pegasi" (Latinised to "Alpha Pegasi") is the star's Bayer designation. It bore the traditional name "Markab" (or "Marchab"), which derived from an Arabic word "مركب" "markab" "the saddle of the horse", or is mistranscription of "Mankib", which itself comes from an Arabic phrase "منكب الفرس" "Mankib al-Faras" "(the Star of) the Shoulder (of the Constellation) of the Horse" for Beta Pegasi.
In 2016, the International Astronomical Union organized a Working Group on Star Names (WGSN) to catalog and standardize proper names for stars. The WGSN's first bulletin of July 2016 included a table of the first two batches of names approved by the WGSN, which included "Markab" for this star.
In Chinese, (), meaning "Encampment", refers to an asterism consisting α Pegasi and β Pegasi. Consequently, the Chinese name for α Pegasi itself is (), "the First Star of Encampment".


NGC 7332

NGC 7332 is an edge-on peculiar lenticular galaxy located about 67 million light-years away. It possesses a (peanut shell)-shaped bulge, associated with stellar bar. It was discovered on September 19, 1784 by the astronomer William Herschel.
NGC 7332 and NGC 7339 form a dynamically isolated binary system (number 570 in the catalog of double galaxies compiled by Igor Karachentsev), and are likely orbiting each other. NGC 7332 is the brighter of the two galaxies.
In the sky NGC 7339 lies 5' away from NGC 7332. NGC 7332 is an unusually blue object with a corrected apparent B-magnitude of 11.5. A 130mm to 200mm telescope will be needed to visually detect this pair of galaxies. The two galaxies will appear at almost a right angle to one another.


NGC 2626

NGC 2626 is a reflection nebula, emission nebula, and absorption nebula in the constellation Vela.


RV Corvi

RV Corvi is an eclipsing binary star system in the constellation Corvus, ranging from apparent magnitude 8.6 to 9.16 over 18 hours. The system is composed of stars of spectral types F0 and G0, which orbit each other every 0.7473 days.


D Velorum

The Bayer designations d Velorum and D Velorum are distinct.
Due to , both designations link here.
For the star :


Kepler-33b

Kepler-33b is an extrasolar planet orbiting Kepler-33 in the constellation Cygnus. It is one of five planets orbiting Kepler-33.
Discovery.
Kepler-33b was, along with twenty-six other planets in eleven different planetary systems, confirmed to be a planet on January 26, 2012.
The Kepler-33 system.
Kepler-33b orbits its host star with 4 other planets. All five planets orbit its star closer than Mercury does to the Sun. Of those five, Kepler-33b is closest. All Kepler-33 planets are too close to be in the habitable zone.
See also.
List of planets discovered by the Kepler spacecraft


Muscida (disambiguation)

The traditional star name Muscida has been applied to:
The name derives from the post classical Latin "musus", meaning "snout, or muzzle [of the bear]".


Chi Ursae Majoris

Chi Ursae Majoris (χ Ursae Majoris, abbreviated Chi UMa, χ UMa), formally named Taiyangshou , is a star in the constellation of Ursa Major. It is approximately 246 light-years from the Sun.
Nomenclature.
"χ Ursae Majoris" (Latinised to "Chi Ursae Majoris") is the star's Bayer designation.
It bore the traditional name "Tai Yang Show", "the Sun Governor", from Chinese astronomy. The name was possibly derived from the word 太陽守, Pinyin: Tàiyángshǒu, meaning "Guard of the Sun", because this star is marking itself and standing alone in the "Guard of the Sun" asterism, Purple Forbidden enclosure (see : Chinese constellations). It also bore traditional names of Arabic origin: "Alkafzah", "Alkaphrah", and "El Koprah".
In 2016, the IAU organized a Working Group on Star Names (WGSN) to catalog and standardize proper names for stars. The WGSN approved the name "Taiyangshou" for this star on 30 June 2017 and it is now so included in the List of IAU-approved Star Names.
Properties.
Chi Ursae Majoris is an evolved, orange hued K-type giant with an apparent magnitude of +3.69. This star has times the radius of the Sun and 1.49 times the Sun's mass.
The spiral galaxy in Ursa Major, NGC 3877 (= H I.201), type Sc, is best found from Chi Ursae Majoris, which is almost exactly 15 arcminutes north of the galaxy.


Arp 7

Arp 7 (PGC 24836) is a spiral galaxy in the constellation Hydra. Redshift-independent measurements of its distance vary widely, from 5.9 Mpc to 83.7 Mpc. Its morphological classification is SB(rs)bc, meaning it is a barred spiral galaxy with some ring-like structure.
Arp 7 was imaged by Halton Arp and included in his Atlas of Peculiar Galaxies under the category of 'split arm' galaxies. Five other galaxies are also included in this section of the atlas: Arp 8 (NGC 497), Arp 9 (NGC 2523), Arp 10 (UGC 1775), Arp 11 (UGC 717), and Arp 12 (NGC 2608).


Lambda Cancri

Lambda Cancri (λ Cancri, abbreviated Lambda Cnc, λ Cnc) is a blue-white hued spectroscopic binary star in the zodiac constellation of Cancer. With a combined apparent visual magnitude of +5.93, it is faintly visible to the naked eye. Based upon parallax measurements obtained during the Gaia mission, it is about 550 light-years distant from the Sun.
The two components are designated Lambda Cancri A (formally named Piautos ) and B.
Nomenclature.
"λ Cancri" (Latinised to "Lambda Cancri") is the binary's Bayer designation. The designations of the two components as "Lambda Cancri A" and "B" derive from the convention used by the Washington Multiplicity Catalog (WMC) for multiple star systems, and adopted by the International Astronomical Union (IAU).
The system occurs in the lunar station that was given the name πιαυτος "piautos" in a Coptic manuscript list of lunar stations, nearly all of which were in "debased" Greek. Crum was of the opinion that "Piautos" is formed from the Greek word "autos" "self" and the Coptic determiner "pi-" "that", which is automatically tacked onto Greek nouns. The combination would (in Greek) mean "the same, the very one". Given that the Greeks are not known to have used lunar stations, the origin of the names is unknown.
In 2016, the IAU organized a Working Group on Star Names (WGSN) to catalog and standardize proper names for stars. The WGSN approved the name "Piautos" for Lambda Cancri on 1 June 2018 and it is now so included in the List of IAU-approved Star Names. The WGSN had previously stated that where a component letter (from e.g. Washington Double Star Catalog) is not explicitly listed, that the name should be understood to be attributed to the brightest component by visual brightness (Lambda Cancri A in this case).
In Chinese, (), meaning "Beacon Fire", refers to an asterism consisting of Lambda Cancri and Psi, Phi1 and 15 Cancri. Consequently, Lambda Cancri itself is known as (, ). From this Chinese name, the name "Kwan Wei" meaning "the bright fire" was given.
Properties.
The primary, Lambda Cancri A, is a B-type main-sequence star with a stellar classification of B9.5 V. It has 2.1 times the mass of the Sun and radiates 78 times the Sun's luminosity from its photosphere at an effective temperature of roughly 9,500 K. Its close companion, Lambda Cancri B, has 80% of the mass of the Sun.


Rho2 Eridani

Rho2 Eridani is a star located in the constellation Eridanus. It forms an asterism with Rho1 and Rho3 Eridani, south of Cetus, in the upper north east portion of Eridanus. The star has an apparent visual magnitude of 5.32, which indicates it is visible to the naked eye on a clear, dark night. Based upon parallax measurements made with the Hipparcos satellite, this star is roughly 260 light years away from the Sun.
This is an evolved K-type giant star with a stellar classification of K0 III. It is a red clump giant on the horizontal branch of the Hertzsprung–Russell diagram, indicating that is it now generating energy through the thermonuclear fusion of helium at its core. The star has 2.5 times the mass of the Sun and has expanded to 9 times the Sun's radius. As such, it is radiating nearly 46 times the solar luminosity from its outer atmosphere at an effective temperature of 4,864 K.
There is a magnitude 9.7 companion star at an angular separation of 1.8″. Most likely the pair form a binary star system. At least one of the stars appears to be a source of X-ray emission. The X-ray band flux is .


ZW II 96

The object ZW II 96 (also II Zw 96) is a pair of galaxies that are merging. It is located in the constellation Delphinus, about 500 million light-years away from Earth.
The shape of the merging galaxies is unusual; a number of powerful young starburst regions hang as long, threadlike structures between the main galaxy cores. The system almost qualifies as an ultraluminous system, but has not yet reached the late stage of coalescence that is the norm for most ultraluminous systems.
The photograph is one of a collection of 59 images of merging galaxies taken by the NASA/ESA Hubble Space Telescope. This collection of images was released on the occasion of the 18th anniversary of Hubble's launch on 24 April 2008.


Omega Fornacis

Omega Fornacis, which is Latinized from ω Fornacis, is a wide binary star system in the southern constellation of Fornax. It has a blue-white hue and is faintly visible to the naked eye as a fifth-magnitude star. The system lies at a distance of approximately 470 light years from the Sun based on parallax, and is drifting further away with a radial velocity of +10 km/s.
The dual nature of this system was discovered in 1836 by John Herschel. As of 2013, the two components had an angular separation of along a position angle of 246°. This corresponds to a projected separation of .
The magnitude 4.95 primary, designated component A, is a chemically peculiar B-type main-sequence star with a stellar classification of B9V It has 3.4 times the Sun's mass and is radiating around 268 times the luminosity of the Sun from its photosphere at an effective temperature of 10,910 K. Component B, the magnitude 7.71 secondary, is an A-type main-sequence star with a class of A3V. It is smaller than the primary, but has a higher projected rotational velocity.


52 Hydrae

52 Hydrae is a triple star system in the constellation Hydra. It has the Bayer designation l Hydrae; "52 Hydrae" is the Flamsteed designation. This system is visible to the naked eye as a faint, blue-white hued star with an apparent visual magnitude of 4.97. It is a probable (80% chance) member of the Sco OB2 moving group of stars, and is moving away from the Earth with a heliocentric radial velocity of 5 km/s.
The primary component is a binary system consisting of two nearly equal components with an orbital period of around and an angular separation of . It shows a combined stellar classification of B7/8V, which matches a B-type main-sequence star. The third component is a magnitude 10.0 star at a separation of with a mass similar to the Sun. It is orbiting the inner pair with a period of around .


Room (Chinese constellation)

The Room mansion (房宿, pinyin: Fáng Xiù) is one of the Twenty-eight mansions of the Chinese constellations. It is one of the eastern mansions of the Azure Dragon.


NGC 2277

NGC 2277 is what appears to be an open cluster in the constellation Gemini. It was first observed on 20 April 1865 by the German astronomer Heinrich Louis d'Arrest. However, it is simply an asterism formed by several stars in the sky appearing close together.


HR 7955

HR 7955 is a binary star system in the northern circumpolar constellation of Cepheus, near the constellation border with Cygnus. It has a yellow-white hue and is faintly visible to the naked eye with a combined apparent visual magnitude of 4.51. The system is located at a distance of 89 light-years (27.3 parsecs) from the Sun, based on parallax. It has a relatively high proper motion, traversing the celestial sphere at the rate of 0.243 arc seconds per annum, and is drifting closer to the Sun with a radial velocity of -33 km/s.
The double-lined nature of this spectroscopic binary system was not announced until 1972. It has an orbital period of and an eccentricity of 0.551. Both components appear to be slightly evolved stars that are leaving the main sequence and becoming subgiant stars, with stellar classifications of F8IV-V and F9IV-V. They each have slightly greater mass than the Sun: 107% and 105%, respectively. The system is about 2.25 billion years old.


List of stars in Andromeda

This is the list of notable stars in the constellation Andromeda, sorted by decreasing brightness.


63 Ophiuchi

63 Ophiuchi is an O-type giant star in the constellation Sagittarius, despite its name. During a 2009 survey for companions of massive stars, it was observed using speckle interferometry but no companion was found. The small parallax measurement of suggest that this extremely luminous star may be located about 3,600 light-years away. An estimate of the distance based on the strength of the Ca II line yields a more modest value of . The star lies only 0.3° north of the galactic plane.
In 1983, astronomers from the Sternberg Astronomical Institute in Moscow, Russia identified a faint, shell-shaped nebula surrounding the star that was being excited by the star's energy. Named Sharpless 22, this ring-shaped nebula has a double-shell structure with an inner envelope spanning 45–50′ (9–18 pc), surrounded by a diffuse envelope some 65–80′ (14–29 pc) across. At an estimated mass loss rate of , it would take the star about to produce such a nebula from the outflow of its stellar wind.


NGC 3972

NGC 3972 is a spiral galaxy located in the constellation of Ursa Major. It was discovered by William Herschel in 1789.


9 Persei

9 Persei is a single variable star in the northern constellation Perseus, located around 4,300 light years away from the Sun. It has the Bayer designation i Persei; "9 Persei" is the Flamsteed designation. This body is visible to the naked eye as a faint, white-hued star with an apparent visual magnitude of 5.17. It is moving closer to the Sun with a heliocentric radial velocity of −15.2 km/s. The star is a member of the Perseus OB1 association of co-moving stars.
This is a blue supergiant with a stellar classification of A2 Ia, a massive star that has used up its core hydrogen and is now fusing heavier elements. It is an Alpha Cygni variable, a type of non-radial pulsating variable, and it ranges in magnitude from 5.15 down to 5.25. The star has 10.5 times the mass of the Sun and has expanded to 89 times the Sun's radius. It is radiating over 12,000 times the luminosity of the Sun from its swollen photosphere at an effective temperature of 9,840 K.
9 Persei has one visual companion, designated component B, at an angular separation of and magnitude 12.0.


Cygnus OB2

Cygnus OB2 is an OB association that is home to some of the most massive and most luminous stars known, including suspected Luminous blue variable Cyg OB2 #12. It also includes one of the largest known stars, NML Cygni. The region is embedded within a wider one of star formation known as Cygnus X, which is one of the most luminous objects in the sky at radio wavelengths. The region is approximately 1,570 parsecs from Earth in the constellation of Cygnus.
The young cluster is one of the largest known and the largest in the northern hemisphere with some authors formerly classifying it as a young globular cluster similar to those in the Large Magellanic Cloud. Today, however, it is considered a massive, low-density stellar association.
Although it is over ten times more massive than the Orion Nebula, which is easily seen with the naked eye, Cygnus OB2 is hidden behind a massive dust cloud known as the Cygnus Rift, which obscures many of the stars in it. This means that despite its large size, it is hard to determine its actual properties. The estimated number of massive stars range from 50 to 100 of spectral type O and its total mass having been calculated as (4–10) or 3 solar masses according to other investigations.
Despite this, recent surveys ranging from radio to X-ray wavelengths have observed the region to great depths to gain a better understanding of how the processes of star and planet formation occur on such a large scale. These studies include observations with the Chandra X-ray Observatory, Spitzer Space Telescope, the Herschel Space Observatory and the Gran Telescopio Canarias. As for recent observations, the final stages of the process of photoablation is taking place, where the biggest stars formed and cleared the ambient material from the region.
The progenitor of BD+43°3654 might be a member in Cygnus OB2 before. Two stars of each binary would collide and merge forming BD+43°3654, that would be ejected from the stellar association along with two other stars.
Prominent members of the association are often referred to by their Schulte numbers: for example Schulte 12, VI Cygni 12, or Cygnus OB2 #12. The numbers were first used in the 1953 discovery paper where 11 "blue giants" were numbered. A 12th star (Cyg OB2 #12) was added in 1954, and eight more shortly after. Schulte himself maintained the already-published numbers and added many more when studying the association which he called VI Cygni.


9 Sagittarii

9 Sagittarii (9 Sgr) is a massive binary star in the constellation Sagittarius. It has an apparent magnitude of 5.97.
Surroundings.
9 Sgr is a naked eye star lying in the direction of the Lagoon Nebula (Messier 8), very close to the central condensation of the Hourglass Nebula around Herschel 36. It was not catalogued by Bayer with a Greek letter, but was listed by Flamsteed as number 9 in the constellation Sagittarius. It lies close to the open cluster NGC 6530. 9 Sgr is the main source of ionisation for much of the visible nebulosity in the region, although the young O star Herschel 36 ionises the dense Hourglass Nebula region.
9 Sgr itself is surrounded by an ionised HII region about 30 light years across including the reflection nebulae NGC 6523 and NGC 6533. This ionised region lies in front of a denser molecular cloud.
The distances to 9 Sgr, M8, and NGC 6530 are uncertain, but generally estimated to be between 1,200 and 1,800 parsecs. Recent studies derive a distance around 1,250 pc for the M8 region. Erosion of the front of the molecular cloud apparently caused by 9 Sgr suggests that it lies in front of the cloud, but studies of 9 Sgr as a binary star give a distance of 1,790 pc.
System.
9 Sagittarii is a binary system with the longest known period for a pair of class O stars at 9.1 years. The orbit is eccentric and the separation between the stars varies from 11 AU to 27 AU. The large separation means that the stellar winds of the two stars do not impact strongly and so the pair are not a strong source of x-rays. Lack of x-rays, low orbital velocities, and similar spectral types merging to a combined spectrum of O4V, mean that 9 Sgr was only confirmed to be a binary in 2012. Earlier clues such as nonthermal radio emission and periodic spectral line profile variations had prompted the detail search for a companion.
The two stars have been resolved using the Hubble Space Telescope Fine Guidance Sensor and with ground-based interferometry using the Very Large Telescope PIONIER instrument.
Properties.
Both components of 9 Sgr are massive main sequence class O stars, and both have temperatures above 40,000 K. Each is several hundred thousand times the luminosity of the sun. As main sequence stars, they are still fusing hydrogen in their cores, although strong convection have enriched the surface with nitrogen and helium which are visible in the spectrum. The powerful stellar winds produce emission lines in their spectra.


NGC 4650A

NGC 4650A is a polar-ring lenticular galaxy located in the constellation Centaurus. It should not be confused with the spiral galaxy NGC 4650, which shares almost the same radial distance as NGC 4650A. The real distance between both galaxies is
only about 6 times the optical radius of NGC 4650.


Zeta Pegasi

Zeta Pegasi (ζ Pegasi, abbreviated Zeta Peg, ζ Peg), formally named Homam , is a single star in the northern constellation of Pegasus. With an apparent visual magnitude of +3.4, this star is bright enough to be seen with the naked eye and is one of the brighter members of Pegasus. Parallax measurements place it at a distance of around from the Sun.
Nomenclature.
"ζ Pegasi" (Latinised to "Zeta Pegasi") is the star's Bayer designation.
It bore the traditional name "Homam", meaning "Man of High Spirit" or "Lucky Star of High Minded". In 2016, the International Astronomical Union organized a Working Group on Star Names (WGSN) to catalogue and standardize proper names for stars. The WGSN approved the name "Homam" for this star on 21 August 2016 and it is now so entered in the IAU Catalog of Star Names.
In Chinese, (), meaning "Thunder and Lightning", refers to an asterism consisting ζ Pegasi, ξ Pegasi, σ Pegasi, 55 Pegasi, 66 Pegasi and 70 Pegasi. Consequently, the Chinese name for ζ Pegasi itself is (), "the First Star of Thunder and Lightning".
Properties.
This star has a stellar classification of B8 V, which identifies it as a large B-type main sequence star that is generating energy through the nuclear fusion of hydrogen at its core. The radius of this star is about four times that of the Sun. It is a slowly pulsating B star that varies slightly in luminosity with a period of 22.952 ± 0.804 hours, completing 1.04566 cycles per day. Zeta Pegasi is about 120 million years old and is rotating rapidly with a projected rotational velocity in the range of . The effective temperature of its outer envelope is around 11,190 K, giving it the characteristic blue-white glow of a B-type star.
Zeta Pegasi has been examined for infrared excess that may indicate the presence of circumstellar matter, but none was found. This star does have two optical companions. The first is a magnitude 11.6 star at an angular separation of 68 arcseconds along a position angle of 139°, as of 1997. The second is an 11th magnitude star at a separation of 177 arcseconds with a position angle of 5°. Zeta Pegasi is not known to be a member of a stellar association.


Zeta Telescopii

Zeta Telescopii (ζ Telescopii) is the second-brightest star in the southern constellation of Telescopium. It is a solitary, orange-hued star that is visible to the naked eye with an apparent visual magnitude of +4.13. Based upon an annual parallax shift of 25.84 mas as seen from Earth, it is located around 127 light years from the Sun.
This is a red clump giant star of spectral type K1 III-IV. The measured angular diameter is . At its estimated distance, this yields a physical size of about 9 times the radius of the Sun. It is around 1.53 times as massive as the Sun and it shines at an effective temperature of 4,801 K.
References.
\end{align}</math></ref>


NGC 3005

NGC 3005 is an edge-on spiral galaxy in the constellation of Ursa Major, discovered by Bindon Stoney on January 25, 1851.
It is a member of the NGC 2998 group, which also includes NGC 2998, NGC 3002, NGC 3006, NGC 3008, and a few others.


Gliese 555

Gliese 555 (HN Librae) is a red dwarf star of spectral type M4.0V, located in constellation Libra at 20.2 light-years from Earth.
Planetary system.
In 2019 one planet been detected by radial velocity among other 118 planets around M dwarf stars.


N Centauri

N Centauri is a binary star in the southern constellation of Centaurus. The brighter star is dimly visible to the naked eye with an apparent visual magnitude of 5.26, and it is approximately 304 light years away based on parallax. It has an absolute magnitude of +0.76 and is drifting further away from the Sun with a radial velocity of +27 km/s. It is a candidate member of the Sco OB2 moving group.
The double nature of this system was discovered by German astronomer Carl Rümker in 1835. As of 2016, the companion lay at an angular separation of along a position angle of 289° from the primary. They form a co-moving pair with a projected separation of . The more luminous member is a B-type main-sequence star with a stellar classification of B9V. Its fainter companion is an F-type main-sequence star with a class of F0Vn, where the 'n' suffix indicates that the metal absorption lines in its spectrum are unusual broad ("nebulous") and indicative of rapid rotation. Based upon discrepancies in the proper motion measurements, there are hints of a third member of this system.


Nu2 Coronae Borealis

Nu2 Coronae Borealis is a solitary, orange-hued star located in the northern constellation of Corona Borealis. It is faintly visible to the naked eye, having an apparent visual magnitude of +5.4. Based upon an annual parallax shift of 5.49 mas, it is located roughly 590 light years from the Sun. At that distance, the visual magnitude is diminished by an extinction of 0.1 due to interstellar dust.
This is an evolved red giant star with a stellar classification of K5 III. The measured angular diameter of Nu2 Coronae Borealis is . At its estimated distance, this yields a physical size of about 50 times the radius of the Sun. Nu2 Coronae Borealis is radiating 530 times the Sun's luminosity from its photosphere at an effective temperature of 3,940 K.
References.
\end{align}</math></ref>


NGC 6638

NGC 6638 is a globular cluster in the constellation Sagittarius. It is magnitude 9.5 and diameter 2 arc minutes, class VI. It is a half degree East of Lambda Sagittarii.
The globular cluster was discovered in 1784 by the astronomer William Herschel with his 18.7-inch telescope and the discovery later in the New General Catalogue.


K2-229

K2-229 (also designated EPIC 228801451 or TYC 4947-834-1) is a K-type main sequence star approximately 103 parsecs (335 light years) away in the constellation Virgo. It was observed by the Kepler Space Telescope during its K2 "Second Light" mission in Campaign 10, and has a system of three confirmed exoplanets.
Planetary System.
As of March 27, 2018, K2-229 has a system of three confirmed planets.
All three known planets transit their star and would orbit inside that of Mercury if placed in our Solar System. Only the innermost has a well determined mass and composition.
K2-229b is a Super-Earth with an iron-rich composition. It is about 17% larger than Earth by radius, but is almost 2.6 times more massive. Its high density indicates it has a core-mass fraction of about 68%, nearly identical to that of Mercury. It is believed that like Mercury, the huge core of K2-229 is the result of a giant impact event. However, unlike Mercury, it orbits extremely close to its host star, with one orbit taking a little over 14 hours to complete. K2-229b has a temperature of over 1,960 K to 2,330 K, hot enough to melt iron and likely giving it an atmosphere of silicate vapor.
K2-229c is a Mini-Neptune sized planet with a radius of 2.12 . Its mass has not been accurately determined, so only an upper limit of 21.3 can be given. However, a different method of radial velocity analysis gives the planet's mass at about 9.5 . With an orbital period of 8.32 days, K2-229c has an equilibrium temperature of and a dayside temperature of .
K2-229d is another Mini-Neptune with a radius of 2.64 , meaning it is likely gaseous. Only a maximum mass of 25.1 could be determined. The planet was detected by a single transit event lasting about two and a half hours long. There were two models for its orbital period: one where it took about 31 days to orbit and the second transit was during a large data gap; and another where it took over 50 days to orbit. The latter scenario was considered unlikely, as K2-229d would need to have a very eccentric orbit to exhibit such a short transit duration – so eccentric that its periapsis would cross the orbit of K2-229c and destabilize the system. It has an equilibrium temperature of .


Xi Serpentis

Xi Serpentis, Latinized from ξ Serpentis, is a triple star system in the Serpens Cauda (tail) section of the equatorial constellation Serpens. Based upon an annual parallax shift of 30.98 mas as seen from Earth, it is located 105.3 light years from the Sun. The star system is visible to the naked eye with a base apparent visual magnitude of +3.54. It is moving closer to the Sun and will make perihelion passage at a distance of in around 690,000 years.
The inner pair form a single-lined spectroscopic binary with an orbital period of 2.29 days following a circular orbit with an eccentricity of 0.00. The primary, component Aa, has a visual magnitude of 3.54. It is a white-hued G-type giant star with a stellar classification of . This indicates it is a chemically peculiar Ap star with an abnormal abundance of strontium. The primary has around double the mass of the Sun, while its close companion, component Ab, has only 18% of the Sun's mass.
The third member, component B, is a magnitude 13.0 common proper motion companion. As of 2012, it was located at an angular separation of 24 arc seconds along a position angle of 78° from the inner pair. It has about 27% of the Sun's mass and an estimated orbital period of 14,763 years.
Name.
In Chinese, "Tiān Shì Zuǒ Yuán" (), meaning "Left Wall of Heavenly Market Enclosure", refers to an asterism which is represent eleven old states (and region) in China which is marking the left borderline of the enclosure, consisting of ξ Serpentis, δ Herculis, λ Herculis, μ Herculis, ο Herculis, 112 Herculis, ζ Aquilae, η Serpentis, θ1 Serpentis, ν Ophiuchi and η Ophiuchi. Consequently, the Chinese name for ξ Serpentis itself is (, ), representing the region of Nanhai (南海, lit. meaning "southern sea")


54 Persei

54 Persei is a single star in the northern constellation of Perseus. It is visible to the naked eye as a faint, yellow-hued star with an apparent visual magnitude of 4.93. The star is located approximately 220 light years away based on parallax, but is drifting closer with a radial velocity of −27 km/s.
This is an aging giant star with a stellar classification of G8+ IIIb, a star that has exhausted the supply of hydrogen at its core and expanded to more than nine times the girth of the Sun. It is around 580 million years old with 2.6 times the mass of the Sun. The star is radiating 51 times the luminosity of the Sun from its enlarged photosphere at an effective temperature of 5,036 K. It has one distant visual companion, designated component B, at an angular separation of and magnitude 13.0.


Water Lily Nebula

The Water Lily Nebula, in the southern constellation of Ara, is a pre-planetary nebula also known as IRAS 16594-4656, in the process of developing to a planetary nebula. It is one of the pre-planetary nebulae containing polycyclic aromatic hydrocarbons, organic hydrocarbons otherwise constituting the basis for life.


Mu Draconis

Mu Draconis (μ Draconis, abbreviated Mu Dra, μ Dra) is a multiple star system near the head of the constellation of Draco. With a combined magnitude of 4.92, it is visible to the naked eye. Based on parallax estimates by the Hipparcos spacecraft, it is located approximately 89 light-years from the Sun.
The system consists of a single primary star (designated Mu Draconis A, officially named Alrakis from the traditional name of the system), a secondary binary pair (Mu Draconis B) and a further single star (C). B's two components are designated Mu Draconis Ba and Bb.
Mu Draconis A and Ba are nearly identical F-type main-sequence stars, with masses of and , respectively. Both have the spectral class of F5V, and have similar apparent magnitude, at 5.66 and 5.69, respectively. The secondary, Mu Draconis B, has a drifting radial velocity, and is itself a spectroscopic binary with an orbital period of 2,270 days. The smaller component, Mu Draconis Bb, has a mass of . Mu Draconis C is a 14th magnitude common-proper-motion companion 13.2" away from the bright pair, with a mass of .
Nomenclature.
μ Draconis (Latinised to "Mu Draconis") is the star's Bayer designation. The designations of the three constituents as "Mu Draconis A", "B" and "C", and those of "B's" components - "Mu Draconis Ba" and "Bb" - derive from the convention used by the Washington Multiplicity Catalog (WMC) for multiple star systems, and adopted by the International Astronomical Union (IAU).
It bore the traditional name "Arrakis" (or "Errakis"), which derives from name given to it by Arabian stargazers, الراقص "al-rāqiṣ" "the trotting (camel)" (lit. "the dancing one".
In 2016, the International Astronomical Union organized a Working Group on Star Names (WGSN) to catalogue and standardize proper names for stars. The WGSN decided to attribute proper names to individual stars rather than entire multiple systems. It approved the name "Alrakis" for the component Mu Draconis A on February 1, 2017 and it is now so included in the List of IAU-approved Star Names.
This star, along with Beta Draconis (Rastaban), Gamma Draconis (Eltanin), Nu Draconis ('Kuma') and Xi Draconis (Grumium) were "Al ʽAwāïd", the Mother Camels, which were known in Latin as the Quinque Dromedarii.
Cultural references.
Science fiction writer Frank Herbert chose Arrakis as the name of the primary planet of Canopus (α Carinae) in his "Dune" series of novels, aware that the word "Arrakis" is the transliteration into English of the Arabic words for "the Dancer" (al-Raqis).


V Aquilae

V Aquilae (V Aql) is a carbon star and semiregular variable star in the constellation Aquila. It has an apparent magnitude which varies between 6.6 and 8.4 and is located around away.
V Aquilae is a type of star with a spectrum that is dominated by strong absorption lines of the molecules C2 and CN, hence known as carbon stars. The enhanced levels of carbon in the atmosphere originate recently nucleosynthesized material that has been dredged up to the surface by deep convection during temporary shell burning events known as thermal pulses. Published spectral types for the star vary somewhat from C54 to C64, or N6 under an older system of classification. The subscript "4" refers to the strength of the molecular carbon bands in the spectrum, an indicator of the relatively abundances of carbon in the atmosphere.
V Aquilae is a variable star of type SRb. It has a published period of 400 days, but other periods are found including 350 days and 2,270 days.


CL Draconis

CL Draconis is a single star in the northern circumpolar constellation of Draco. It can be viewed with the naked eye, having an apparent visual magnitude of 4.96. The distance to this star, as determined from its annual parallax shift of , is 109 light years. It is moving closer to the Earth with a heliocentric radial velocity of −11 km/s. The star has a relatively high proper motion, traversing the celestial sphere at the rate of /yr.
Based upon a stellar classification of F0 IV, this is an aging F-type subgiant star that has consumed the hydrogen at its core. It is spinning rapidly with a projected rotational velocity of 165 km/s, giving it an oblate shape with an equatorial bulge that is estimated to be 8% larger than the polar radius. CL Dra is a Delta Scuti variable, changing brightness with an amplitude of 0.010 magnitude over a period of . CL Dra has 1.68 times the mass of the Sun and is radiating 10.2 times the Sun's luminosity from its photosphere at an effective temperature of 7,439 K.


F Velorum

The Bayer designations f Velorum and F Velorum are distinct. Due to , both designations link here. For the star


NGC 490

NGC 490, also occasionally referred to as PGC 4973 or GC 277, is a lenticular galaxy in the constellation Pisces. It is located approximately 85 million light-years from Earth and was discovered on December 6, 1850, by Irish engineer Bindon Blood Stoney. Although John Dreyer, creator of the New General Catalogue, credits the discovery to astronomer William Parsons, he notes that many of his claimed discoveries were made by one of his assistants. In the case of NGC 490, the discovery was made by Bindon Stoney, who discovered it along with NGC 486, NGC 492 and NGC 500 during his observation of NGC 488.
The object was initially described in the New General Catalogue as "very faint, very small, round, 8 arcmin northeast of h 103 (=NGC 488)".


NGC 6284

NGC 6284 is a globular cluster located in the constellation Ophiuchus. It is designated as IX in the galaxy morphological classification scheme and was discovered by the German-born British astronomer William Herschel on 22 May 1784. It is at a distance of 49,900 light years away from earth.<ref name="NASA/IPAC"></ref>
The nearby metal-poor star may be a recent runaway from NGC 6284.


HD 20468

HD 20468 is a class K2II (orange bright giant) star in the constellation Perseus. Its apparent magnitude is 4.82 and it is approximately 1180 light years away based on parallax.


78 Virginis

78 Virginis is a variable star in the zodiac constellation of Virgo, located 175 light-years from the Sun. It has the variable star designation CW Virginis and the Bayer designation o Virginis; "78 Virginis" is the Flamsteed designation. This object is visible to the naked eye as a faint, white-hued star with an apparent visual magnitude of 4.92. It is moving closer to the Earth with a heliocentric radial velocity of −10 km/s.
This is an Ap star with a stellar classification of ApEuCrSr, displaying strong lines of strontium, chromium, and other iron peak elements. It is classified as an Alpha2 Canum Venaticorum variable, ranging in magnitude from 4.91 down to 4.99 with a period of 3.722 days. 78 Virginis is the first star other than the Sun to have a magnetic field detected; it displays a dipole structure with a surface intensity of around . It is a candidate rapidly oscillating Ap (roAp) star. This star is 435 million years old with 2.16 times the mass of the Sun and 2.11 times the Sun's radius. It is radiating 27 times the Sun's luminosity from its photosphere at an effective temperature of 9,100 K.


Mu Coronae Australis

μ Coronae Australis, Latinized as Mu Coronae Australis, is a solitary star located in the southern constellation of Corona Australis. It is a yellow-hued star and is visible to the naked eye with an apparent visual magnitude of 5.217. Parallax measurements put it at a distance of approximately 387 light-years from the Sun, but it is drifting closer with a radial velocity of −16 km/s. It has an absolute magnitude of -0.37.
This object is an aging G-type giant star with a stellar classification of G5-6III. It is roughly 361 million years old with 3.065 times the mass of the Sun. Having exhausted the supply of hydrogen at its core, the star has cooled and expanded away from the main sequence. At present it has 11 times the girth of the Sun. The star is radiating 111 times the luminosity of the Sun from its swollen photosphere at an effective temperature of 5,557 K.


NGC 2354

NGC 2354 is an open cluster in the constellation Canis Major. It lies 2 degrees southwest from NGC 2362 and northeast of Delta Canis Majoris. About 15 member stars are visible through binoculars.


NGC 6755

NGC 6755 is an open cluster in the constellation Aquila.


HCM-6A

HCM-6A is an LAE galaxy that was found in 2002 by a team led by Esther Hu from the University of Hawaii, using the Keck II Telescope in Hawaii. HCM-6A is located behind the Abell 370 galactic cluster, near M77 in the constellation Cetus, which enabled the astronomers to use Abell 370 as a gravitational lens to get a clearer image of the object.
HCM-6A was the farthest object known at the time of its discovery. It exceeded SSA22−HCM1 ("z" = 5.74) as the most distant normal galaxy known, and quasar SDSSp J103027.10+052455.0 ("z" = 6.28) as the most distant object known. In 2003, SDF J132418.3+271455 ("z" = 6.578) was discovered, and took over the title of most remote object known, most remote galaxy known, and most remote normal galaxy known.


NGC 784

NGC 784 is a barred spiral galaxy about 16.0 Mly away in the constellation Triangulum. NGC 784 is located within the Virgo Supercluster.


HD 56405

HD 56405 is a star in the southern constellation of Canis Major. It is white in hue and is dimly visible to the naked eye with an apparent visual magnitude of 5.45. To the east of HD 56405 is the open cluster NGC 2360, also known as Caroline's Cluster. The distance to HD 56405, as determined from parallax measurements, is approximately 249 light years. It is drifting further away with a radial velocity (RV) of about +6 km/s. Although classed as a single star, it is to suspected to vary in RV.
This is an A-type main-sequence star with a stellar classification of A1V. It was classed as a candidate Lambda Boötis star, but as of 2015 this classification has been rejected by astronomers due to the star having an inconsistent UV flux, possible RV variability, and a fairly high rotation rate. The star is about 212 million years old with 2.13 times the mass of the Sun and is spinning with a projected rotational velocity of 149 km/s. It is radiating 39 times the luminosity of the Sun from its photosphere at an effective temperature of around 9,562 K.


Mintaka

Mintaka , designation Delta Orionis (δ Orionis, abbreviated Delta Ori, δ Ori) and 34 Orionis (34 Ori), is a multiple star system some 1,200 light-years from the Sun in the constellation of Orion. Together with Alnitak (Zeta Orionis) and Alnilam (Epsilon Orionis), the three stars form Orion's Belt, known by many names among ancient cultures. The star is located very close to the celestial equator. When Orion is near the meridian, Mintaka is the rightmost of the Belt's stars when viewed from the Northern Hemisphere facing south.
Nomenclature.
"Delta Orionis" is the star's Bayer designation, "34 Orionis" its Flamsteed designation. The name "Mintaka" itself is derived from an Arabic term for 'belt': منطقة or "manṭaqa". In 2016, the International Astronomical Union organized a Working Group on Star Names (WGSN) to catalog and standardize proper names for stars. The WGSN's first bulletin of July 2016 included a table of the first two batches of names approved by the WGSN, which included "Mintaka" for this star. It is now so entered in the IAU Catalog of Star Names.
Observational history.
Mintaka is the westernmost of the three stars of Orion's belt. It is easily visible to the naked eye, one of the brightest stars in the sky, and has been known since antiquity.
Radial velocity measurements taken by Henri-Alexandre Deslandres in 1900 at Paris Observatory showed that Mintaka had a variable radial velocity and therefore was a spectroscopic binary. His preliminary orbital period estimate of 1.92 days was shown to be incorrect in 1904 when Johannes Franz Hartmann using photographic plates taken at Potsdam Observatory showed that the orbital period was 5.7 days. Hartmann also noticed that the calcium K line at 393.4 nanometres in the stellar spectrum did not share in the periodic displacements of the lines due to orbital motion of the star and theorized that there was a cloud in the line of sight to Mintaka that contained calcium. This was the first detection of the interstellar medium.
System.
δ Orionis is a multiple star system. There is a magnitude 7 star about 52 arcseconds away from the second-magnitude primary and a much fainter star in between. The system is designated WDS 05320-0018 in the Washington Double Star Catalog, with the 14th-magnitude companion listed as component B and the seventh-magnitude star as component C.
The primary component is itself a triple system: a class O9.5 bright giant and a class B main-sequence star orbit every 5.73 days and exhibit shallow eclipses when the star dims about 0.2 magnitudes, and a B-class sub-giant is resolved 0.26" away. At the primary eclipse, the apparent magnitude (of the whole system) drops from 2.23 to 2.35, while it only drops to 2.29 at the secondary eclipse.
The seventh-magnitude companion, HD 36485, is a chemically peculiar B-type main-sequence star and itself a spectroscopic binary with a faint A-type companion in a 30-day orbit. It has an unusual spectrum with H-alpha emission and unusually strong helium absorption lines. It has a strong magnetic field and a very slow rotational velocity that produces chemical stratification in its atmosphere, which leads to the unusual abundances seen in the spectrum.
The 14th magnitude companion is thought to be around the same distance and is a somewhat cooler and less luminous star than the Sun.
Mintaka is surrounded by a cluster of faint stars, possibly part of the cluster surrounding σ Ori.
Distance.
The distance derived from the Hipparcos satellite parallax is , while spectroscopic distances, comparisons to similar stars, and cluster membership all suggest a value more than double that. This type of unreconcilable discrepancy is not unique to Mintaka and the reasons for it have yet to be clarified. In Gaia Data Release 2, components B and C are listed with parallaxes of and , respectively, implying distances considerably further than the Hipparcos-derived value for the primary.
Etymology and cultural significance.
Mintaka was seen by astrologers as a portent of good fortune.
Orion's Belt.
The three belt stars were collectively known by many names in many cultures. Arabic terms include "Al Nijād" 'the Belt', "Al Nasak" 'the Line', "Al Alkāt" 'the Golden Grains or Nuts', and, in modern Arabic, "Al Mīzān al Ḥakk" 'the Accurate Scale Beam'. In Chinese mythology, they were also known as the Weighing Beam.
In Chinese, (), meaning "Three Stars (asterism)", refers to an asterism consisting of Mintaka, Alnilam, and Alnitak (Orion's Belt), with Betelgeuse, Bellatrix, Saiph, and Rigel later added. Consequently, the Chinese name for Mintaka is (, ). It is one of the western mansions of the White Tiger.
Namesakes.
The USS "Mintaka" (AK-94) was a United States Navy "Crater"-class cargo ship named after the star.


74 Orionis

74 Orionis is a single star in the equatorial constellation of Orion. It has the Bayer designation k Orionis, while "74 Orionis" is the Flamsteed designation. This object is visible to the naked eye as a faint, yellow-white hued point of light with an apparent visual magnitude of 5.04. It is located at a distance of 64 light years from the Sun based on parallax, and is drifting further away with a radial velocity of +9 km/s. The star has a relatively high proper motion, traversing the celestial sphere at the rate of 0.204 arc seconds per annum.
This object is an ordinary F-type main-sequence star with a stellar classification of F5V. It is an estimated 2.3 billion years old and is spinning with a projected rotational velocity of 18.8 km/s. The star has 1.4 times the mass of the Sun and 1.3 times the Sun's radius. Metallicity is near solar, which indicates it has a Sun-like abundances of elements. The star is radiating three times the luminosity of the Sun from its photosphere at an effective temperature of 6,595 K.
74 Orionis has two visual companions: component B, with magnitude 12.5 and separation 32.1", and C, with magnitude 9.0 and separation 195.5".


56 Ceti

56 Ceti is a single star located in the equatorial constellation of Cetus. Not found in the original Bayer catalogue, it was given the Bayer-like designation Upsilon1 Ceti by Flamsteed to distinguish it from Bayer's Upsilon Ceti, which Flamsteed designated Upsilon2 or 59 Ceti. In 1801, J. E. Bode included this designation in his "Uranographia", but the superscripted designations Upsilon1 and Upsilon2 are not in general use today. "56 Ceti" is the Flamsteed designation for this star.
This star is visible to the naked eye as a faint, orange-hued point of light with an apparent visual magnitude of 4.85. It is located about 440 light years from the Sun, based on parallax, and is drifting further away with a radial velocity of +27 km/s. 56 Ceti is an aging giant star with a stellar classification of K3III, having exhausted the supply of hydrogen at its core and expanded to 39 times the Sun's radius. It is radiating 391 times the luminosity of the Sun from its enlarged photosphere at an effective temperature of 4,099 K.


TW Hydrae

TW Hydrae is a T Tauri star approximately 196 light-years away in the constellation of Hydra (the Sea Serpent). The star is the closest such star to the Solar System. TW Hydrae is about 80% of the mass of the Sun, but is only about 5-10 million years old. The star appears to be accreting from a face-on protoplanetary disk of dust and gas, which has been resolved in images from the ALMA observatory. TW Hydrae is accompanied by about twenty other low-mass stars with similar ages and spatial motions, comprising the "TW Hydrae association" or TWA, one of the closest regions of recent "fossil" star-formation to the Sun.
Stellar characteristics.
TW Hydrae is a pre-main-sequence star that is approximately 80% the mass of and 111% the radius of the Sun. It has a temperature of 4000 K and is about 8 million years old. In comparison, the Sun is about 4.6 billion years old and has a temperature of 5778 K. The star's luminosity is 28% that of the Sun.
The star's apparent magnitude, or how bright it appears from Earth's perspective, is 11.7. It is too dim to be seen with the naked eye.
Planetary system.
The star is known to host one likely exoplanet, TW Hydrae b.
Protoplanetary disk.
Previously disproven protoplanet.
In December 2007, a team led by Johny Setiawan of the Max Planck Institute for Astronomy in Heidelberg, Germany announced discovery of a planet orbiting TW Hydrae, dubbed "TW Hydrae b" with a minimum mass around 1.2 Jupiter masses, a period of 3.56 days, and an orbital radius of 0.04 astronomical units (inside the inner rim of the protoplanetary disk). Assuming it orbits in the same plane as the outer part of the dust disk (inclination 7±1°), it has a true mass of 9.8±3.3 Jupiter masses. However, if the inclination is similar to the inner part of the dust disk (4.3±1.0°), the mass would be 16 Jupiter masses, making it a brown dwarf. Since the star itself is so young, it was presumed this is the youngest extrasolar planet yet discovered, and essentially still in formation.
In 2008 a team of Spanish researchers concluded that the planet does not exist: the radial velocity variations were not consistent when observed at different wavelengths, which would not occur if the origin of the radial velocity variations was caused by an orbiting planet. Instead, the data was better modelled by starspots on TW Hydrae's surface passing in and out of view as the star rotates. "Results support the spot scenario rather than the presence of a hot Jupiter around TW Hya". Similar wavelength-dependent radial velocity variations, also caused by starspots, have been detected on other T Tauri stars.
New study of more distant planet.
In 2016, ALMA found evidence that a possible Neptune-like planet was forming in its disk, at a distance of around 22 AU.
Detection of methanol.
In 2016, methanol, one of the building blocks for life, was detected in the star's protoplanetary disk.


Alpha Reticuli

Alpha Reticuli (Alpha Ret, α Reticuli, α Ret) is the Bayer designation of the brightest star in the southern circumpolar constellation of Reticulum, with an apparent visual magnitude of 3.3. This appears to be a solitary star located at a distance of 162 light-years from Earth. Although it is bright enough to be seen with the naked eye, the declination of this star means that it is best viewed from the southern hemisphere and is only readily visible below the tropic of cancer.
This star has more than three times the mass of the Sun and is about 330 million years old. The spectrum of this star matches a stellar classification of G8 II-III, with the luminosity class notation 'II-III' indicating it shows some traits of both a giant star and a bright giant. At this evolutionary stage, the atmosphere has expanded to almost thirteen times the radius of the Sun and the outer envelope has an effective temperature of 5,196 K. X-ray emission has been detected from this star, with an estimated luminosity of .
Alpha Reticuli has a 12th-magnitude visual companion, CCDM J04144-6228B, at an angular separation of 48 arcseconds away along a position angle of 355°. Since the two stars share a common proper motion across the celestial sphere, it is possible that Alpha Reticuli, rather than being solitary, may instead be the primary component of a binary star system with an orbital period of, at least, 60,000 years.
Naming.
In Chinese, caused by adaptation of the European southern hemisphere constellations into the Chinese system, (), means "White Patches Attached", and it refers to an asterism consisting of α Reticuli and θ Doradus. Consequently, α Reticuli itself is known as (, .)


60 Cancri

60 Cancri is a star in the zodiac constellation Cancer, located about 850  light years away from the Sun. It is visible to the naked eye as a faint, orange-hued star with an apparent visual magnitude of +5.44. 60 Cancri is situated near the ecliptic, so it is subject to the occasional occultation by the Moon. It is moving away from the Earth with a heliocentric radial velocity of +25 km/s.
This is an aging giant star with a stellar classification of K5 III, indicating it has exhausted the hydrogen at its core and evolved off the main sequence. It is a suspected variable star of unknown type. The interferometry-measured angular diameter of the primary component, after correcting for limb darkening, is , which, at its estimated distance, equates to a physical radius of about 54 times the radius of the Sun. It is around 1.15 billion years old with 1.4 times the mass of the Sun. The star is radiating 670 times the Sun's luminosity from its enlarged photosphere at an effective temperature of 4,150 K.
References.
\end{align}</math></ref>


NGC 475

NGC 475 is a lenticular galaxy in the constellation Pisces. It is located approximately 750 million light-years from Earth and has a diameter of roughly 125 thousand light-years. NGC 475 was discovered on November 3, 1864 by German astronomer Albert Marth.


Delta Lyrae

The Bayer designation Delta Lyrae (δ Lyr / δ Lyrae) is shared by a star and a star system, in the constellation Lyra (constellation):


Iota2 Fornacis

Iota2 Fornacis is the Bayer designation for a star in the southern constellation of Fornax. It is faintly visible to the naked eye on a dark night, having an apparent visual magnitude of 5.83. The distance to this star, based upon an annual parallax shift of 29.46 mas, is around 111 light years. It is a member of the thin disk population of the Milky Way galaxy.
This is an F-type main sequence star with a stellar classification of . The suffix notation indicates that absorption lines of iron and the carbon-hydrogen G-band are abnormally weak. It has an estimated 1.42 times the mass of the Sun and 1.4 times the Sun's radius. The star is around 3.67 billion years old, and is spinning with a leisurely projected rotational velocity of 4.7 km/s.
Iota2 Fornacis has a common proper motion companion, a magnitude 13.74 star at a position angle of 81.80 arc seconds along a position angle of 6°. This object has about 35% of the Sun's mass.


Tau Cancri

Tau Cancri (τ Cancri) is a solitary, yellow-hued star in the zodiac constellation of Cancer. With an apparent visual magnitude of +5.42, it is faintly visible to the naked eye. Based upon an annual parallax shift of 11.92 mas as seen from Earth, it is located around 274 light years from the Sun.
With an age of about 620 million years and a stellar classification of G8 III, this is a red clump giant star, which indicates that it has evolved onto the horizontal branch and is generating energy through helium fusion at its core. It is a microvariable, showing a luminosity variation of 0.04 in magnitude. Tau Cancri has an estimated 2.4 times the mass of the Sun and 7.8 times the Sun's radius. The star radiates 40 times the solar luminosity from its photosphere at an effective temperature of 5,153 K.


Rho Puppis

Rho Puppis (ρ Puppis, abbreviated Rho Pup, ρ Pup), formally named Tureis , is a star in the southern constellation of Puppis. With an average apparent visual magnitude of 2.78, it is the third-brightest member of this generally faint constellation. Based upon parallax measurements made during the Hipparcos mission, Rho Puppis is located at a distance of from the Sun. It is the prototype of the ρ Puppis class of evolved Am stars.
Nomenclature.
"ρ Puppis" (Latinised to "Rho Puppis") is the star's Bayer designation.
It bore the traditional name "Tureis" or "Turais", from the Arabic "تُرَيْس" "turays" "shield" (diminutive), which was shared by Iota Carinae. In 2016, the International Astronomical Union organized a Working Group on Star Names (WGSN) to catalogue and standardize proper names for stars. The WGSN approved the name "Tureis" for this star on 12 September 2016 and it is now so entered in the IAU Catalog of Star Names (Iota Carinae was given the name "Aspidiske" on 20 July 2016).
Properties.
At present Rho Puppis is moving away from the Sun with a radial velocity of +46.1 km s−1. The closest approach occurred about 394,000 years ago when it came within roughly of the Solar System; about the same distance as Procyon in the present era.
The variability of this star was announced in 1956 by American astronomer Olin J. Eggen. It was determined to be a Delta Scuti-type variable star, making it one of the first stars of that type to be identified. Photometric observations dating back to 1946 provide a lengthy record of its pattern of pulsation; it undergoes periodic pulsations with a single period of 0.14088143(3) days, or 7.1 cycles per day. During each cycle, the star's magnitude varies with an amplitude of 0.15 and the radial velocity varies by 10 km s−1. The peak brightness occurs 28.8 minutes following the minimum radial velocity. The outer atmosphere's effective temperature of 6,920 K is one of the lowest known for a Delta Scuti variable.
Rho Puppis has an estimated age of about 2 billion years and it has 3.4 times the Sun's radius. It has a stellar classification of F5IIkF2IImF5II. This complex format indicates that ρ Puppis is an Am star, with relatively weak lines of calcium and strong lines of other metals. The spectral type indicated by the calcium k line is F5, while that indicated by heavier metal absorption lines is F2. The roman numerals indicate a luminosity class of bright giant. Most such stars are found in binary star systems, but this appears to be an exception as no companion has been discovered. Evolved stars with Am-like peculiarities of abundance have come to be known as ρ Puppis stars. The star's metallicity is more than double that in the Sun.
This star shows an excess emission of infrared radiation, suggesting that there is a circumstellar disk of dust orbiting this star. The mean temperature of the emission is 85 K, corresponding to an orbital separation from the host star of 50 AU.


3 Geminorum

3 Geminorum is a blue supergiant star in the constellation Gemini. It is a small amplitude pulsating variable and a close double star, with a mean combined apparent visual magnitude of 5.75.
3 Geminorum was found to be an α Cygni variable in 1998 and given the designation PU Geminorum. It varies by a few tenths of a magnitude with a main period of 3.81 days.
3 Geminorum is also a close double star. The brighter component is the variable blue supergiant. The companion is 2.5 magnitudes fainter. The separation is about 0.6 arc-seconds. There is also a much fainter, approximately 14th magnitude, star 14" away.
Faint Hα emission lines have been detected in the spectrum of 3 Geminorum, but this is not usually expressed in published spectral classifications. An "e" is only occasionally appended to the spectral type to reflect the emission lines. MK spectral types consistently classify 3 Geminorum as a normal supergiant (luminosity class Ib), although spectral classes derived in other ways often result in a bright supergiant (Ia) luminosity class.
3 Geminorum can be occulted by the Moon. Observations of these occulations can give information about the angular diameter of a star, or about close companions. Occultations of 3 Geminorum have been observed, but no double or diameter information has been published.


80 Cancri


Delta Ceti

Delta Ceti, Latinized from δ Ceti, is a single, blue-white hued star in the equatorial constellation of Cetus. The star's apparent visual magnitude of +4.06 means it is near to the cusp of the faintest third of the stars that are visible the ideally-placed naked eye. It is north of the celestial equator compared to the celestial north pole's . It is about WNW of the spiral galaxy M77 (but which at apparent magnitude 9.6 needs magnification to be made out and has an apparent size of by ).
Distance and relative motion.
Based upon an annual parallax shift of as seen from Earth, it is around from the Sun.
Motion relative to our system's trajectory includes a highly parting vector: with a net radial velocity of about . It moves minutely across the celestial sphere – yet just over four times more in right ascension than in declination.
Inherent properties.
This is a Beta Cephei variable with a stellar classification of B2 IV. It varies in brightness with a period of 0.16114 days. The star is about 7−18 million years and has a low projected rotational velocity of around , suggesting it is either rotating slowly or is being viewed from nearly pole on. It has 8.4 times the mass of the Sun and 4.6 times the Sun's radius. The star is radiating around 4,000 times the Sun's luminosity from its photosphere at an effective temperature of roughly
Name.
This star, along with α Cet (Menkar), λ Cet (Menkar), γ Cet (Kaffaljidhma), μ Cet, ξ1 Cet and ξ2 Cet were "Al Kaff al Jidhmah", "the Part of a Hand".
According to the catalogue of stars in the "Technical Memorandum 33-507 - A Reduced Star Catalog Containing 537 Named Stars", "Al Kaff al Jidhmah" were the title for five stars :γ Cet as "Kaffaljidhma", ξ1 Cet as "Al Kaff al Jidhmah I", ξ2 Cet as "Al Kaff al Jidhmah II", δ Cet as "Al Kaff al Jidhmah III" and μ Cet as "Al Kaff al Jidhmah IV" (exclude α Cet and λ Cet.)
In Chinese, (), meaning "Circular Celestial Granary", refers to an asterism consisting of δ Ceti, α Ceti, κ1 Ceti, λ Ceti, μ Ceti, ξ1 Ceti, ξ2 Ceti, ν Ceti, γ Ceti, 75 Ceti, 70 Ceti, 63 Ceti and 66 Ceti. Consequently, the Chinese name for δ Ceti itself is (, .)


64 Eridani

64 Eridani is a single, yellow-white hued star in the constellation Eridanus having variable star designation S Eridani. It is faintly visible to the naked eye with an apparent visual magnitude of 4.77. The annual parallax shift is measured at , which equates to a distance of about . In addition to its proper motion, it is moving closer to the Sun with a radial velocity of around −9 km/s.
This is an F-type main-sequence star with a stellar classification of F0 V. It is catalogued a low amplitude Delta Scuti variable with a primary period of 0.273 days. It was originally classified, tentatively, as an RR Lyrae variable of type 'c'.
64 Eridani is spinning rapidly with a projected rotational velocity of 212 km/s. This is giving the star an oblate shape with an equatorial bulge; its equatorial radius is 8% larger than its polar radius. The star is an estimated 644 million years old with 1.5 times the mass of the Sun. It is radiating 80 times the Sun's luminosity from its photosphere at an effective temperature of roughly 7,346 K.


28 Aurigae

28 Aurigae (28 Aur) is a star in the constellation Auriga. Its apparent magnitude is 6.80. It is a giant star which has exhausted its core hydrogen and expanded to ten times the size of the Sun. Despite being slightly cooler than the sun at it is 73 times more luminous. Its distance is known quite accurately at around .
28 Aurigae is one of the few faint Flamsteed stars which is not in the Bright Star Catalogue. It is included in the Hipparcos catalogue and its parallax was calculated to be . Its Gaia Data Release 2 parallax is very similar, but more precise at


69 Aquilae

69 Aquilae, abbreviated 69 Aql, is a star in the equatorial constellation of Aquila. "69 Aquilae" is its Flamsteed designation. It is visible to the naked eye with an apparent visual magnitude of 4.91. Based upon an annual parallax shift of , it is located 201 light years away. The star is moving closer to the Earth with a heliocentric radial velocity of −22.5 km/s.
The stellar classification of 69 Aquilae is K1/2 III, which means this is an evolved giant star. It belongs to a sub-category called the red clump, indicating that it is on the horizontal branch and is generating energy through helium fusion at its core. The star is about 3.4 billion years old with 1.54 times the mass of the Sun and has expanded to 11 times the Sun's radius. It is radiating 45.7 times the Sun's luminosity from its enlarged photosphere at an effective temperature of 4,529 K.


Tau Tauri

Tau Tauri, Latinized from τ Tauri, is a quadruple star system in the constellation Taurus. It is visible to the naked eye as a faint point of light with a combined apparent visual magnitude of 4.33. The distance to this system is approximately about 400 light years based on parallax. The system is moving further from the Earth with a heliocentric radial velocity of +14.6 km/s, and it is a member of the Taurion OB association, located between Orion and Taurus. It is located 0.7 degree north of the ecliptic, and thus is subject to lunar occultations.
The blue-white hued primary, component Aa, is a B-type main-sequence star with a stellar classification of B3V. It was found to be a close spectroscopic binary in 1903 by American astronomers Edwin B. Frost and Walter S. Adams. The pair have an orbital period of 2.96 days and eccentricity of 0.05. A second companion, white-hued component Ab, has magnitude 6.97 and angular separation 0.2" from the primary in a 58-year orbit. This is a probably A-type main-sequence star with a class of A0V–A2V. The more distant component B is a type A1V star with magnitude 7.2 and separation 62.8".


Nu Caeli

Nu Caeli (ν Caeli) is a yellow-white hued star in the constellation Caelum. It has an apparent visual magnitude of 6.07, which indicates it is near the lower limit on brightness that is visible to the naked eye. According to the Bortle scale, the star can be viewed from dark suburban skies. Based upon an annual parallax shift of as seen from Earth, this star is located from the Sun.
Houk (1978) listed a stellar classification of F2/3 V for Nu Caeli, which would indicate this is an F-type main-sequence star. In contrast, Malaroda (1975) assigned it to class F1 III-IV, which would suggest it is a more evolved F-type subgiant/giant transitional object. It is an estimated 880 million years old with 1.34 times the mass of the Sun. The star is radiating eight times the Sun's luminosity from its photosphere at an effective temperature of .
A companion is listed in multiple star catalogues. It is a 10th-magnitude star about away, much further away than ν Caeli and unrelated.


NGC 5026

NGC 5026 is a barred spiral galaxy or lenticular galaxy in the constellation of Centaurus. It was discovered on 5 June 1834 by John Herschel. It was described as "pretty bright, pretty large, round, gradually brighter middle" by John Louis Emil Dreyer, the compiler of the New General Catalogue.


YZ Canis Minoris

YZ Canis Minoris is a red-hued star in the equatorial constellation of Canis Minor. With an apparent visual magnitude of 11.15, it is much too faint to be viewed with the naked eye. The distance to YZ CMi can be estimated from its annual parallax shift of , yielding a value of 19.5 light years. Presently the star is moving further away with a heliocentric radial velocity of +26.5 km/s. It made its closest approach some 162,000 years ago when it made perihelion passage at a distance of . YZ CMi is a potential member of the Beta Pictoris moving group.
This is a red dwarf star, or M-type main-sequence star, with a stellar classification of M5 V. It is a flare star, so called due to its solar flares being more powerful than those of Earth's star, and is roughly three times the size of Jupiter. The radio emission from the star is in a 50 mHz bandwidth and is centered on 1464.9 mHz. The X-ray surface flux is . It has a coronal temperature of .


Omega Geminorum

Omega Geminorum, Latinized from ω Geminorum, is a star located in the middle of the northern zodiac constellation of Gemini. With an apparent visual magnitude of 5.18, it is faintly visible to the naked eye. According to the Bortle scale, it can be viewed from dark suburban skies. With an annual parallax shift of just 2.19 mas, it is located about 1,500 light years from the Sun.
This is an evolved bright giant star with a stellar classification of G5 II. It is positioned near the instability strip and in 1977 was listed as a candidate cepheid variable star with a luminosity amplitude of 0.086 and a period of 0.7282 days. The interferometer-measured angular diameter of this star is . At its estimated distance, this yields a physical size of about 72 times the radius of the Sun. It has 6.3 times the mass of the Sun and radiates 1,813 times the solar luminosity from its outer atmosphere at an effective temperature of 5,090 K.
References.
\end{align}</math></ref>


UW Coronae Borealis

UW Coronae Borealis, also known as MS 1603.6+2600, is a low-mass X-ray binary star system in the constellation Corona Borealis. Astronomer Simon Morris and colleagues discovered the X-ray source in 1990 and were able to match it up with a faint star with an average visual magnitude of 19.4. The system is thought to be made up of a neutron star that has an accretion disk that draws material from its companion, a star less massive than the Sun. The disk is asymmetrical. The variability of the system is complex, with several periods identified: the two components orbit each other every 111 minutes, while there is another period of 112.6 minutes. The beat period of these is 5.5 days, which is thought to represent the precession of the asymmetrical accretion disk around the neutron star.


56 Sagittarii

56 Sagittarii is a single star in the southern constellation of Sagittarius. It has the Bayer designation f Sagittarii, while "56 Sagittarii" is the Flamsteed designation. This object is visible to the naked eye as a faint, orange-hued point of light with an apparent visual magnitude of 4.87. It is located approximately 208 light years away from the Sun based on parallax, and is drifting further away with a radial velocity of +22 km/s.
This is an aging giant star with a stellar classification of K0+III, having exhausted the supply of hydrogen at its core and expanded to 11 times the Sun's radius. It is a red clump giant, which means it is on the horizontal branch and is generating energy through helium fusion at its core. The star has 1.8 times the mass of the Sun and is radiating 59 times the Sun's luminosity from its enlarged photosphere at an effective temperature of 4,750 K.


Lambda Herculis

Lambda Herculis (λ Herculis. abbreviated Lambda Her, λ Her), formally named Maasym , is a star in the constellation of Hercules. From parallax measurements taken during the Hipparcos mission, it is approximately 370 light-years from the Sun.
Nomenclature.
"λ Herculis" (Latinised to "Lambda Herculis") is the star's Bayer designation.
It bore the traditional name "Maasym", from the Arabic مِعْصَم "miʽṣam" "wrist". In 2016, the International Astronomical Union organized a Working Group on Star Names (WGSN) to catalogue and standardize proper names for stars. The WGSN approved the name "Maasym" for this star on 12 September 2016 and it is now so included in the List of IAU-approved Star Names.
In Chinese, (), meaning "Left Wall of Heavenly Market Enclosure", refers to an asterism which represents eleven old states in China and which is marking the left borderline of the enclosure, consisting of Lambda Herculis, Delta Herculis, Mu Herculis, Omicron Herculis, 112 Herculis, Zeta Aquilae, Theta1 Serpentis, Eta Serpentis, Nu Ophiuchi, Xi Serpentis and Eta Ophiuchi. Consequently, the Chinese name for Lambda Herculis itself is (, ), and represents the state Zhao (or Chaou (趙)), together with 26 Capricorni and 27 Capricorni ("m Capricorni" in R.H.Allen version) in "Twelve States" (asterism).
Description.
Lambda Herculis has apparent magnitude +4.4 spectral class K4III, indicating that it is a red giant with a temperature of . Visually it has an absolute magnitude of −0.86, meaning it is nearly 200 times brighter than the sun, but its bolometric luminosity across all wavelengths is .
In 1783, English-German astronomer William Herschel described the solar apex, the point in sky towards which the Solar System is moving; using data from double stars, he identified this position as close to Lambda Herculis. Today it is known the solar apex is not so close to this star, however it is only 10° away from the position currently accepted (in Hercules, southwest of Vega).


B Cygni

The Bayer designation b Cygni is shared by three stars in the constellation Cygnus:
See also.
Albireo (β Cygni)


BL Lacertae

BL Lacertae or "BL Lac" is a highly variable, extragalactic active galactic nucleus (AGN or active galaxy). It was first discovered by Cuno Hoffmeister in 1929, but was originally thought to be an irregular variable star in the Milky Way galaxy and so was given a variable star designation. In 1968, the "star" was identified by John Schmitt at the David Dunlap Observatory as a bright, variable radio source. A faint trace of a host galaxy was also found. In 1974, Oke and Gunn measured the redshift of BL Lacertae as z = 0.07, corresponding to a recession velocity of 21,000 km/s with respect to the Milky Way. The redshift figure implies that the object lies at a distance of 900 million light years.
Due to its early discovery, BL Lacertae became the prototype and namesake of the class of active galactic nuclei known as "BL Lacertae objects" or "BL Lac objects". This class is distinguished by rapid and high-amplitude brightness variations and by optical spectra devoid (or nearly devoid) of the broad emission lines characteristic of quasars. These characteristics are understood to result from relativistic beaming of emission from a jet of plasma ejected from the vicinity of a supermassive black hole. BL Lac objects are also categorized as a type of blazar.
BL Lacertae changes in apparent magnitude over fairly small time periods, typically between values of 14 and 17. In January 2021, it exhibited extreme flaring behavior and was reported to reach magnitude 11.45 in the R filter band.


Chi Hydrae

The Bayer designation Chi Hydrae (χ Hya / χ Hydrae) is shared by two star systems, in the constellation Hydra:


Kepler-56b

Kepler-56b (KOI-1241.02) is an exoplanet located roughly 3,060 light years away. It is somewhat
larger than Neptune and orbits its parent star Kepler-56 and was discovered in 2013 by the Kepler Space Telescope.
Planetary orbit.
Kepler-56b is about 0.1028 AU away from its host star (about one-tenth of the distance between Earth to the Sun), making it even closer to its parent star than Mercury and Venus. It takes 10.5 days for Kepler-56b to complete a full orbit around Kepler-56. Further research shows that Kepler-56b's orbit is about 45° misaligned to the host star's equator. Later radial velocity measurements have revealed evidence of a gravitational perturbation but currently it is not clear if it is a nearby star or a third planet (a possible Kepler-56d).
Both Kepler-56b and Kepler-56c will be devoured by their parent star in about 130 and 155 million years. Even further research shows that it will have its atmosphere boiled away by intense heat from the star, and it will be stretched by the strengthening stellar tides.
The measured mass of Kepler-56b is about 30% larger than Neptune's mass, but its radius is roughly 70% larger than Neptune's. Therefore, Kepler-56b should have a hydrogen/helium envelope containing a significant fraction of its total mass. Like Kepler-11b and Kepler-11c, the envelope's light elements are susceptible to photo-evaporation caused by radiation from the central star. For example, it has been calculated that Kepler-11c lost over 50% of its hydrogen/helium envelope after formation. However, the larger mass of Kepler-56b, compared to that of Kepler-11c, reduces the efficiency of mass loss. Nonetheless, the planet may have been significantly more massive in the past and may keep losing mass in the future.


NGC 7742

NGC 7742 also known as Fried Egg Galaxy is a face-on unbarred spiral galaxy in the constellation Pegasus. It is also classified as a Type II Seyfert Galaxy.
The galaxy is unusual in that it contains a ring but no bar. Typically, bars are needed to produce a ring structure. The bars' gravitational forces move gas to the ends of the bars, where it forms into the rings seen in many barred spiral galaxies. In this galaxy, however, no bar is present, so this mechanism cannot be used to explain the formation of the ring. O. K. Sil'chenko and A. V. Moiseev proposed that the ring was formed partly as the result of a merger event in which a smaller gas-rich dwarf galaxy collided with NGC 7742. As evidence for this, they point to the unusually bright central region, the presence of highly inclined central gas disk, and the presence of gas that is counterrotating (or rotating in the opposite direction) with respect to the stars.
Two Type II supernovae, SN 1993R and SN 2014cy, have been detected in NGC 7742.


Five Chariots

Five Chariots (五車, pinyin: Wǔ Ju) is a constellation in Chinese astronomy.
Introduction.
A five-star Chinese constellation equivalent to Auriga minus δ Aur (Delta Aurigae). Also known in Japanese as Gosha (Five Chariots; 五車).
Characteristics.
The Five Chariots otherwise known as Auriga is a constellation that borders Taurus. The constellation is named as such due to the five main stars, representing the five celestial emperors. The constellation appears within the region of the sky dominated by the White Tiger of the West. Within the region of the White Tiger of the West there are seven mansions, the Five Chariots resides under the net mansion.
Five Celestial Emperors.
The Five Celestial Emperors (Wu Ti) represent the five elements. Four of them represent the four seasons, but the fifth represents the center, otherwise known as the circumpolar region. The Eastern Emperor, T'ai Hao, represents wood. The Northern Emperor represents fire, and the Southern Emperor represents water. The one in the middle known as Shao Hao is associated with earth. Finally the Western Emperor, Huang Ti, represents the element metal. They can be recognized by the v-necked coats they wear, this is the case with most major divinities, as well as the regions they occupy. These emperors were in control of life and death, and as such people regularly made sacrifices, or gave offerings, to them. The Celestial Emperors are often depicted in mirrors. They also appear often in the sarcophagi of people that were important during this time period as they played a major role in funerals. This is due to the fact that the emperors are constantly controlling life and death.
Planets.
All of the emperors can also be represented by certain planets, for example, the Southern Emperor is often associated with the "fire star" otherwise known as Mars. The Eastern emperor is associated with the "wood star" equivalent to Jupiter. Venus is associated with the Western Emperor as Venus was known as the "metal star". The "water star", known today as Mercury is associated with the Northern Emperor. Lastly the Emperor of the Center is represented by the "Earth star" also known as Saturn.
Colors.
Another distinction that can be attributed to each of the emperors is a specific color. The emperor of the East is represented by green, the South red, the Center yellow, the West white, and the North black. Each of the colors that are associated with the Celestial emperors have their own meaning in Chinese culture. The color green is representative of spring, wood, and things that taste sour. White represents metal, as well as fall. It can also be associated with an acrid taste. Black can be seen to represent winter and the element of water, as well as the taste of salt. Yellow is seen as being related to earth and a sweet taste, there is no season as this is the Central Emperor. Summer, fire, and a bitter taste can be related to the color red.
Natures.
Each divinity is often associated with a certain nature, regarding their characteristics as individual deities. The Black Emperor, also known as the Black Ruler is represented as a dark warrior. A green dragon is often associated with the Green Ruler. The Red Ruler is often regarded as a scarlet bird. The White Ruler is associated with a white tiger. Lastly the Yellow Ruler is represented by a unicorn. These distinctions directly correlate with the representation of areas of the celestial realm. There is The dark warrior of the North, The Azure Dragon of the East, The Vermillion Bird of the South, and the White Tiger of the West.