Gliese 3685

Gliese 3685 is a star in the constellation of Leo. It is extremely faint; its apparent magnitude is 13.3, and can only be seen with a ten-inch (25 cm) telescope (see Limiting magnitude). Based on a parallax of 50.30 milliarcseconds, the system is located 65 light years (20 parsecs) away from the Earth.
This is a part of a binary star system consisting of two components separated by 24″. The primary component, Gliese 3685 (also known as Gliese 3685 A), is a very old red dwarf that is also a flare star. A 20-minute flare was observed in 2004 by the GALEX satellite. Its companion, Gliese 3686, is another faint red dwarf with a spectral type of M5. It is also known as LP 613-50 and is also located roughly the same distance as its primary.


NGC 284

NGC 284 is an elliptical galaxy in the constellation Cetus. It was discovered on October 2, 1886 by Francis Leavenworth.


Cygnus OB7

Cygnus OB7 is an OB association in the Milky Way Galaxy in the Cygnus molecular cloud complex, which also contains the star-forming regions Cygnus X, the North America Nebula, and the Pelican Nebula. The Northern Coal Sack lies in the foreground of this region.


LQ Andromedae

LQ Andromedae (shortened as LQ And, also known as HR 9070 in the Bright Star Catalogue) is a variable star in the constellation Andromeda. Its maximum apparent visual magnitude is 6.5, placing it at the limit of the visibility to the naked eye. The brightness, however, drops down to 6.66 with a periodic cycle of roughly 7.44 hours.
The stellar classification of this star is B4Ven, so it is a main sequence star that shows emission lines and broadened absorption lines induced by the fast projected rotational velocity of 300 km/s (the angle between the rotation axis and our line of sight has been estimated with a value of 72°). This leads to the classification of the star as a Be star. Further proof is the compatibility between the rotational and luminosity variability periods.
LQ Andromedae is also a spectroscopic binary with an orbital period of 7.413 days. Not much is known about the secondary component, but it is likely a low-mass companion (M<0.5 ). A circumstellar disk is also present in the system.


Gamma Ceti

Gamma Ceti (γ Ceti, abbreviated Gamma Cet, γ Cet) is a triple star system in the equatorial constellation of Cetus. It has a combined apparent visual magnitude of 3.47. Based upon parallax measurements, this star is located at a distance of about 80 light-years (24.4 parsecs) from the Sun.
The three components are designated Gamma Ceti A (officially named Kaffaljidhma , the traditional name for the entire system), B and C.
Nomenclature.
"γ Ceti" (Latinised to "Gamma Ceti") is the system's Bayer designation. The designations of the three components as "Gamma Ceti A", "B" and "C" derive from the convention used by the Washington Multiplicity Catalog (WMC) for multiple star systems, and adopted by the International Astronomical Union (IAU). The close pair AB is also designated HIP 12706, HD 16970, and HR 804. The system of A, B, and C is collectively designated GJ 106.1 in the Gliese Catalogue of Nearby Stars.
Gamma Ceti bore the traditional names of or , derived from ('the cut-short hand'). According to a 1971 NASA memorandum, was originally the title for five stars: Gamma Ceti as , Xi1 Ceti as , Xi2 Ceti as , Delta Ceti as and Mu Ceti as (excluding Alpha Ceti and Lambda Ceti). The IAU Working Group on Star Names (WGSN) approved the name "Kaffaljidhma" for the component Gamma Ceti A on February 1, 2017.
In Chinese astronomy, , meaning 'Circular Celestial Granary', refers to an asterism consisting of Gamma Ceti, Alpha Ceti, Kappa1 Ceti, Lambda Ceti, Mu Ceti, Xi1 Ceti, Xi2 Ceti, Nu Ceti, Delta Ceti, 75 Ceti, 70 Ceti, 63 Ceti and 66 Ceti. Consequently, the Chinese name for Gamma Ceti itself is ('the Eighth Star of Circular Celestial Granary').
Triple system.
Gamma Ceti appears to be a triple star system. The inner pair (A and B) have an angular separation of 2.6 arcseconds. The primary component of this pair (A) is an A-type main sequence star with a stellar classification of A3 V and a visual magnitude of 3.6. The fainter secondary component (B) is an F-type main sequence star that has a classification of F3 V and a magnitude of 6.6. The contrasting colors of these two stars makes them a popular target of amateur astronomers. The two can be resolved with a small, aperture telescope under ideal seeing conditions, although at times they can be a challenge to resolve even with a much larger scope.
At a wide separation of 840 arcseconds is component C, a dim, magnitude 10.2 K-type star with the designation . It shares a common proper motion with A and is at a very similar distance, but is separated from the close pair by over . It has a spectral classification of K5V. There are several other stars brighter and closer to Gamma Ceti than – , HD 16985, and – but they are all more distant background stars.
Properties.
The measured angular diameter of the primary star is . At the estimated distance of this system, this yields a physical size of about 1.9 times the radius of the Sun. The secondary component of this system is an X-ray source with a luminosity of . Gamma Ceti is about 300 million years old, and it appears to be a member of the stream of stars loosely associated with the Ursa Major Moving Group. The primary has been examined for an excess of infrared emission that would suggest the presence of circumstellar matter, but none was found.
References.
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NGC 6207

NGC 6207 is a spiral galaxy located in the constellation Hercules. It is designated as SA(s)c in the galaxy morphological classification scheme and was discovered by William Herschel on 16 May 1787. NGC 6207 is located at about 30 million light-years from earth. It is located near the globular cluster Messier 13.<ref name="NASA/IPAC"></ref>


Kappa Cygni

Kappa Cygni, Latinized from κ Cygni, is a star in the northern constellation of Cygnus. It has an apparent visual magnitude of 3.8, which is bright enough to be seen with the naked eye. In the constellation, it forms the tip of Cygnus the swan's left wing. The radiant of the minor Kappa Cygnids meteor shower is located about 5° north of this star.
Examination of this star's spectrum show it to match a stellar classification of G9 III, with the 'III' luminosity class revealing that it has consumed the hydrogen fuel at its core and expanded into the giant star stage of its stellar evolution. It is known to vary in luminosity, but only by about 0.01 to 0.02 magnitudes. The measured angular diameter of this star, after correction for limb darkening, is . At an estimated distance of based on parallax measurements, this yields a physical size of about 8–9 times the radius of the Sun. The outer envelope has an effective temperature of 4,920 K, giving it the yellow-orange hue of a star near the transition from a G- to a K-type classification.
References.
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Psi6 Aurigae

Psi6 Aurigae, Latinized from ψ6 Aurigae, is a spectroscopic binary star in the northern constellation of Auriga. It is a dim, naked eye star with an apparent visual magnitude of +5.22. Based upon a measured annual parallax shift of , it is approximately distant from the Earth.
This is a single-lined spectroscopic binary star system with an orbital period of 5,996 days (16.4 years) and an eccentricity of 0.044. The visible component is a K-type giant star with a stellar classification of K0.5 III. It is most likely (78% chance) on the red giant branch and is around 1.55 billion years old. As such, it has an estimated double the mass of the Sun and about 18 times the Sun's radius. The star is radiating about 123 times the Sun's luminosity from its photosphere at an effective temperature of 4,574 K.


Sextans B

Sextans B (also known as UGC 5373 and DDO 70) is an irregular galaxy that may be part of the Local Group, or lie just beyond it. Sextans B is 4.44 million light-years away from Earth and thus is one of the most distant members of the Local Group, if it is indeed a member. It forms a pair with its neighbouring galaxy Sextans A. It is a type Ir IV-V galaxy according to the galaxy morphological classification scheme. Sextans B may also be gravitationally associated with the galaxies NGC 3109 and the Antlia Dwarf.
Sextans B has a uniform stellar population, but the interstellar medium in it may be inhomogeneous. Its mass is estimated to be about 2 × 108 times the mass of the Sun, of which 5.5 × 107 is in the form of atomic hydrogen. Star formation in the galaxy seems to have proceeded in distinct periods of low intensity, separated by shorter periods of no activity. The existence of Cepheid variables in the galaxy implies that Sextans B contains at least some young stars. The metallicity of Sextans B is rather low, with a value of approximately Z = 0.001. Sextans B is receding from the Milky Way with a speed of approximately , and probably lies just outside the edge of the Local Group, so as its neighbour Sextans A.
Five planetary nebulae have been identified in Sextans B, which is one of the smallest galaxies where planetary nebulae have been observed. These appear point-like and can be identified by their spectral emission lines. It also contains a massive globular cluster.


70 Virginis

70 Virginis is a single star located 58 light years from the Sun in the equatorial constellation of Virgo, near the northern constellation border with Coma Berenices. "70 Virginis" is its Flamsteed designation. The star is visible to the naked eye as a faint, yellow-hued point of light with an apparent visual magnitude of +4.97. It is drifting further away with a heliocentric radial velocity of +4.4 km/s and has a high proper motion, traversing the celestial sphere at the rate of 0.621 arc seconds per annum.
This object has a stellar classification of G4 V-IV, being rather unusually bright for a main sequence star of its type and thus may be just starting to evolve into the subgiant phase. It is an estimated 7.9 billion years old and is spinning with a projected rotational velocity of 4.8 km/s. The star has 1.12 times the mass of the Sun and 1.9 times the Sun's radius. It is radiating 2.92 times the luminosity of the Sun from its photosphere at an effective temperature of 5,406 K. The metallicity – a term astronomers use to describe the abundance of elements heavier than helium – is near solar.
In 1996, 70 Virginis was discovered to have an extrasolar planet in orbit around it. There is also an orbiting dusty disc with an average temperature of 153 K located at a mean distance of 3.4 AU from the star.
Planetary system.
The discovery of the planet around 70 Virginis was announced on January 17, 1996 at the meeting of the American Astronomical Society in San Antonio, Texas. The planet was detected using radial velocity measurements taken with the C. Donald Shane telescope at Lick Observatory. It has an orbital period of 117 days, an eccentricity of 0.4, and a mass at least 7.4 times that of Jupiter.


BF Antliae

BF Antliae, or HD 86301, is a variable star in the southern constellation of Antlia. It has a baseline apparent visual magnitude of 6.32, which indicates it lies near the lower limit of visibility for faint stars. The distance to BF Ant, as determined from its annual parallax shift of , is 473 light years. It is moving further away with a heliocentric radial velocity of +18 km/s.
This is an A-type main-sequence star with a stellar classification of A4 V that is at the end of its main sequence lifespan. It is a Delta Scuti variable that varies by 0.01 of a magnitude. These are short-period (six hours at most) pulsating stars that have been used as standard candles and as subjects to study astroseismology. Handler and Shobbrook (2002) noted that the star lies near the "hot luminous border of the δ Scuti instability strip", and it appears "multiperiodic with a time scale of 3.8–6 hours".
BF Antliae is spinning rapidly with a projected rotational velocity of 219 km/s. It has 2.41 times the mass of the Sun and is radiating 67 times the Sun's luminosity from its photosphere at an effective temperature of 7,745 K.


T Centauri

T Centauri is a variable star located in the far southern constellation Centaurus. It varies between magnitudes 5.56 and 8.44 over 181.4 days. Pulsating between spectral classes K0:e and M4II:e, it has been classed as a semiregular variable, though Sebastian Otero of the American Association of Variable Star Observers has noted its curve more aligned with RV Tauri variable stars and has classified it as one.


NGC 884

NGC 884 (also known as χ Persei) is an open cluster located 7600 light years away in the constellation of Perseus. It is the easternmost of the Double Cluster with NGC 869. NGC 869 and 884 are often designated h and χ Persei, respectively. The cluster is most likely around 12.5 million years old. Located in the Perseus OB1 association, both clusters are located physically close to one another, only a few hundred light years apart. The clusters were first recorded by Hipparchus, but have likely been known since antiquity.
The Double Cluster is a favorite of amateur astronomers. These bright clusters are often photographed or observed with small telescopes. Easy to find, the clusters are visible with the unaided eye between the constellations of Perseus and Cassiopeia as a brighter patch in the winter Milky Way. The Double Cluster was also included in the Caldwell catalogue, a catalogue of astronomical objects for amateur observation.
In small telescopes, the cluster appears as a beautiful assemblage of bright stars located in a rich star field. Dominated by bright blue stars, the cluster also hosts a few orange stars that add to the visual interest. Both clusters together offer a spectacular low-magnification view.


NGC 3553

NGC 3553 is a lenticular galaxy in the constellation Ursa Major. It was discovered in March 1885 by Guillaume Bigourdan. It is a member of the galaxy cluster Abell 1185.


PT Puppis

PT Puppis (PT Pup) is a star in the constellation Puppis. Anamarija Stankov confirmed this star as a Beta Cephei variable. Analysis of its spectrum and allowing for extinction gives a mass 7.94 times that of the Sun, a surface temperature of 19,400 K and luminosity of 6405 Suns.


HD 92788

HD 92788 is a star in the equatorial constellation of Sextans. It has a yellow hue but is too dim to be visible to the naked eye, having an apparent visual magnitude of 7.31. The star is located at a distance of 113 light years from the Sun based on parallax, but is drifting closer with a radial velocity of −4.5 km/s. Two planets have been found in orbit around the star.
This is a G-type main-sequence star with a stellar classification of G6V. It is estimated to be around eight billion years old and is spinning with a rotation period of 31.7 days. The star has a similar mass to the Sun and is slightly larger in radius, with a high metallicity. It is radiating 1.25 times the luminosity of the Sun from its photosphere at an effective temperature of 5,722 K.
Planetary system.
An extrasolar planet was discovered orbiting this star in 2001 by means of the radial velocity method. Designated component 'b', it is a Super-Jupiter or possibly a low-mass brown dwarf with an orbital period of . The star rotates at an inclination of 8 degrees relative to Earth. It is probable that this planet shares that inclination.
A low-mass brown dwarf companion was announced in 2019. Designated component 'c', it orbiting with a period of around and a semimajor axis of .


NGC 623

NGC 623 is a large elliptical galaxy located in the Sculptor constellation about 400 million light-year from the Milky Way. It was discovered by British astronomer John Herschel in 1837.


V538 Aurigae

V538 Aurigae is a single star in the northern constellation of Auriga. With an apparent visual magnitude of 6.23, this star requires good dark sky conditions to view with the naked eye. It is located at a distance of from Sun based on parallax. The star is drifting further away with a radial velocity of 0.9 km/s. It is a member of the Local Association, and is most likely a thin disk star.
This is a BY Draconis variable, which means it undergoes changes in luminosity because regions of pronounced surface magnetic activity are moved into and out of the line of sight from the Earth as the star rotates (once every 11 days). It has a spectral class of K1 V, indicating that it is a K-type main sequence star. The star has 87% of the mass of the Sun and 82% of the Sun's radius. It is an estimated 3.76 billion years old. The star is radiating 48% of the Sun's luminosity from its photosphere at an effective temperature of 5,303 K.
It has a common proper motion companion designated Vys 465 (HD 233153), which is a red dwarf with a class of M0.5V and a visual magnitude of 9.87. Their projected separation is .


NGC 7077

 NGC 7077 is a lenticular blue compact dwarf galaxy located about 56 million light-years away from Earth in the constellation Aquarius. Discovered by astronomer Albert Marth on August 11, 1863, the galaxy lies within the Local Void.


Beta Lacertae

Beta Lacertae (Beta Lac, β Lacertae, β Lac) is the fourth-brightest star in the constellation of Lacerta. Based upon an annual parallax shift of 19.19 mas, it is 170 light years distant from Earth. At that distance, the visual magnitude is diminished by an extinction factor of 0.17 due to interstellar dust.
This is an evolved G-type giant with an apparent visual magnitude of approximately 4.43. It is a red clump star and the primary component of a suspected binary system, with the pair having an angular separation of 0.2 arc seconds.
Naming.
In Chinese, (), meaning "Flying Serpent", refers to an asterism consisting of β Lacertae, α Lacertae, 4 Lacertae, π2 Cygni, π1 Cygni, HD 206267, ε Cephei, σ Cassiopeiae, ρ Cassiopeiae, τ Cassiopeiae, AR Cassiopeiae, 9 Lacertae, 3 Andromedae, 7 Andromedae, 8 Andromedae, λ Andromedae, κ Andromedae, ι Andromedae, and ψ Andromedae. Consequently, the Chinese name for β Lacertae itself is (, )


Delta Reticuli

Delta Reticuli (Delta Ret, δ Reticuli, δ Ret) is a star in the southern constellation of Reticulum. It is visible to the naked eye, having an apparent visual magnitude of 4.60. The distance to this star, as estimated from its annual parallax shift of 6.20 mas, is roughly 530 light-years from the Sun.
This is an evolved red giant star on the asymptotic giant branch, having a stellar classification of M2 III. It has expanded to around 56 times the radius of the Sun and radiates 1,100 times the solar luminosity from its cool outer atmosphere at an effective temperature of 3,891 K.
Delta Reticuli is moving through the Milky Way at a speed of 13.3 km/s relative to the Sun. Its projected galactic orbit carries it between 22,700 and 30,400 light-years from the center of the galaxy.


Sigma Coronae Borealis

Sigma Coronae Borealis (σ CrB) is a star system in the constellation of Corona Borealis. It is a quintuple star system containing three sunlike main-sequence stars and two other low-mass stars. The combined visual magnitude is 5.3 and the system lies 74 light years from Earth. σ CrB A is the variable star TZ Coronae Borealis.
System components.
The brightest components of Sigma Coronae Borealis form a visual binary first resolved in the 19th century, and are designated σ Corona Borealis A and B. More recently, the designations σ2 and σ1 Corona Borealis have come into use. Somewhat confusingly, the brighter component A is referred to as σ2 because it has the higher right ascension. A third component, while being separated by (translating to a minimum distance of 14,000 au), has a similar parallax and proper motion to the brighter stars and is physically associated. It is known in the Washington Double Star Catalog (WDS), a compilation of observations of double stars, as component E, but it is usually called Sigma Coronae Borealis C.
Sigma1 Corona Borealis is a G-type main-sequence star like the Sun, and has similar parameters: a mass roughly equal to that of the Sun, and an effective temperature of 5950 K. A visual orbit has been calculated, with a period of about 730 years and a high eccentricity of 0.72.
Sigma2 Corona Borealis itself is a close binary. Here, the two stars are extremely close and orbit fairly quickly, every 1.14 days. This tiny separation of only 0.0279 au has allowed the two stars to exert tidal forces on each other, leading to synchronization of their rotation. They have also been classified as RS Canum Venaticorum variables (RS CVn)—young, active stars that show variability in their apparent magnitude due to starspots on their surfaces.
Despite Sigma2 Corona Borealis's two stars being separated only by about the diameter of each star, they were resolved using the CHARA optical interferometer at the Mount Wilson Observatory. As of 2006, it is the shortest-period binary ever to be resolved. The primary is 13.7% more massive than the Sun, while the secondary is 9.0% more massive than the Sun, and both are 24.4% wider than the Sun.
σ Coronae Borealis C, also known as HIP 79551, appears as a red dwarf with a spectral type of M2.5V. It too is a binary star, with a companion in a 52-year orbit. The companion has a mass of and has been detected through astrometry.
Optical companions.
The Washington Double Star Catalog (WDS), a compilation of observations of double stars, lists several components to the main system. Two of those are listed in the WDS as components C, and D. As of 1984, component C was separated from the primary by along a position angle of 103° and as of 1996, component D was separated from the primary by along a position angle of 82°. However, both of them have different proper motions through space and are not related, just optical alignments.
Variability.
The spectroscopic binary σ2 CrB is an RS Canum Venaticorum variable. It varies in brightness by 0.05 magnitudes every 1.139789 days, the same as the orbital period. The brightness changes are caused by variations in surface brightness on the stars, effectively giant sunspots. Variable star designations are not given to stars with Bayer designations, but in this case only one component of σ Coronae Borealis is identified as variable, so it has the designation TZ Coronae Borealis.


Palomar 5

Palomar 5 is a globular cluster discovered by Walter Baade in 1950. It was independently found again by Albert George Wilson in 1955. After the initial name of Serpens, it was subsequently catalogued as Palomar 5.
There is a process of disruption acting on this cluster because of the gravitation of the Milky Way - in fact there are many stars leaving this cluster in the form of a stellar stream. The stream has a mass of 5000 solar masses and is 30,000 light years long. The cluster is currently from the Galactic Center. It shows a noticeable amount of flattening, with an aspect ratio of between its semimajor axis and semiminor axis.


V752 Centauri

V752 Centauri (HD 101799) is multiple star system and variable star in the constellation of Centaurus. An eclipsing binary, its apparent magnitude has a maximum of 9.10, dimming to 9.66 during primary eclipse and 9.61 during secondary eclipse. Its variability was discovered by Howard Bond in 1970. From parallax measurements by the Gaia spacecraft, the system is located at a distance of from Earth.
V752 Centauri is a contact binary of the W Ursae Majoris type, composed of two F-type stars with a combined spectral type of F7/G0(V). Individually, the components have been classified as F8 + F5, and F8 + F7.5. With effective temperatures of 5,955 and 6,221 K, the system is classified as a W Ursae Majoris variable of subtype W, where the secondary star is hotter than the primary; for this reason, the primary eclipses are caused by the occultation of the secondary star. The system has an orbital period of only 0.3702 days and a separation of 2.59 solar radii. The orbit is inclined by 82° in relation to the plane of the sky.
The combination of photometric and spectroscopic data have allowed the direct determination of the parameters of the stars. The primary component has a mass of 1.31 times the solar mass, radius of 1.30 times the solar radius and a luminosity double that of the Sun. The secondary has only 0.39 times the solar mass, 0.77 times the solar radius, and 0.75 times the solar luminosity. Since the stars are in contact, there is considerable mass transfer from the secondary to the primary. It is estimated that the secondary star was initially the more massive star, with 1.76 times the solar mass, while the primary had an initial mass of 0.84 time the solar mass. The system's age is estimated at 3.8 billion years. All contact binary stars are expected to eventually merge into a single, fast-rotating star.
The system's spectrum shows the spectral lines of a third star, which seems to be a K-type main sequence star. This third star is itself a spectroscopic binary with a period of 5.147 days, with a small companion that is probably an M-type red dwarf. The V752 Centauri system is thus composed of four stars, with two binary pairs that orbit each other. Most contact binary stars have one or more distant companions, and were possibly formed by angular momentum loss due to gravitational interactions with these companion stars.
The light curve analysis of V752 Centauri reveals that between 1970 and 2000, the orbital period of the eclipsing binary remained approximately constant, indicating there was no significant mass transfer. Around the year 2000, the period abruptly increased, possibly accompanied by a slightly dimmer primary eclipse. Since then, the period has been increasing at a rate of 0.044 seconds per year, which is caused by mass transfer from the less massive star to the more massive one at a rate of 2.52  per year. This period change and the beginning of the mass transfer phase were possibly caused by interactions with the companion binary star.


Bellatrix

Bellatrix , designation γ Orionis (Latinized to Gamma Orionis, abbreviated to Gamma Ori, γ Ori), is the third-brightest star in the constellation of Orion, 5° west of the red supergiant Betelgeuse (Alpha Orionis). With a slightly variable magnitude of around 1.6, it is about the 25th-brightest star in the night sky.
Nomenclature.
The traditional name "Bellatrix" is from the Latin "bellātrix" "female warrior"; it first appeared in the works of Abu Ma'shar al-Balkhi and Johannes Hispalensis, where it originally referred to Capella, but was transferred to Gamma Orionis by the Vienna school of astronomers in the 15th century, and appeared in contemporary reprints of the "Alfonsine tables". 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 "Bellatrix" for this star. It is now so entered in the IAU Catalog of Star Names. The designation of Bellatrix as γ Orionis (Latinized to Gamma Orionis) was made by Johann Bayer in 1603. The "gamma" designation is commonly given to the third-brightest star in each constellation
Physical properties.
Bellatrix is a massive star with about 8.6 times the Sun's mass. It has an estimated age of approximately 25 million years—old enough for a star of this mass to consume the hydrogen at its core and begin to evolve away from the main sequence into a giant star. The effective temperature of the outer envelope of this star is , which is considerably hotter than the 5,778 K on the Sun. This high temperature gives this star the blue-white hue that occurs with B-type stars. The measured angular diameter of this star, after correction for limb darkening, is  mas. At an estimated distance of , this yields a physical size of about six times the radius of the Sun.
Bellatrix was thought to belong to the Orion OB1 Association of stars that share a common motion through space, along with the stars of Orion's Belt: Alnitak (Zeta Orionis), Alnilam (Epsilon Orionis), and Mintaka (Delta Orionis). However, this is no longer believed to be the case, as Bellatrix is now known to be much closer than the rest of the group. It is not known to have a stellar companion, although researchers Maria-Fernanda Nieva and Norbert Przybilla raised the possibility it might be a spectroscopic binary. A 2011 search for nearby companions failed to conclusively find any objects that share a proper motion with Bellatrix. Three nearby candidates were all found to be background stars.
Standard star.
Bellatrix has been used as both a photometric and spectral standard star, but both characteristics have been shown to be unreliable.
In 1963, Bellatrix was included with a set of bright stars used to define the UBV magnitude system. These are used for comparison with other stars to check for variability, and so by definition, the apparent magnitude of Bellatrix was set to 1.64. However, when an all-sky photometry survey was carried out in 1988, this star was itself found to be variable. It ranges in apparent magnitude from 1.59 to 1.64.
The spectral types for O and early B stars were defined more rigorously in 1971 and Bellatrix was used as a standard for the B2 III type. The expected brightness of Bellatrix from this spectral type is about one magnitude brighter than calculated from its apparent magnitude and Hipparcos distance. Analysis of the observed characteristics of the star indicate that it should be a B2 main sequence star, not the giant that it appears from its spectral type. Close analysis of high resolution spectra suggest that it is a spectroscopic binary composed of two similar stars less luminous than a B2 giant.
Etymology and cultural significance.
Bellatrix was also called the Amazon Star, which Richard Hinckley Allen proposed came from a loose translation of the Arabic name "Al Najīd", the Conqueror. A c.1275 Arabic celestial globe records the name as المرزم "the lion". Bellatrix is one of the four navigational stars in Orion that are used for celestial navigation.
In the 17th century catalogue of stars in the "Calendarium" of Al Achsasi al Mouakket, this star was designated "Menkib al Jauza al Aisr", which was translated into Latin as "Humerus Sinister Gigantis".
The Wardaman people of northern Australia know Bellatrix as "Banjan", the sparkling pigment used in ceremonies conducted by Rigel the Red Kangaroo Leader in a songline when Orion is high in the sky. The other stars of Orion are his ceremonial tools and entourage. Betelgeuse is "Ya-jungin" "Owl Eyes Flicking", watching the ceremonies.
To the Inuit, the appearance of Betelgeuse and Bellatrix high in the southern sky after sunset marked the beginning of spring and lengthening days in late February and early March. The two stars were known as "Akuttujuuk" "those (two) placed far apart", referring to the distance between them, mainly to people from North Baffin Island and Melville Peninsula.
References.
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NGC 2423-3 b

NGC 2423-3b is an extrasolar planet approximately 2498 light-years away in the constellation of Puppis. The planet was announced in 2007 to be orbiting the red giant star NGC 2423-3 (which in turn is part of the NGC 2423 open cluster). The planet has a mass at least 10.6 times that of Jupiter. Only the minimum mass is known since the orbital inclination is not known, so it may instead be a brown dwarf.
This planet was discovered by Christophe Lovis and Michel Mayor in June 2007. Lovis had also found three Neptune-mass planets orbiting HD 69830 in May 2006, also in Puppis.


IM Pegasi

IM Pegasi is a variable binary star system approximately 329 light-years away in the constellation of Pegasus. With an apparent magnitude of 5.7, it is visible to the naked eye. Increased public awareness of it is due to its use as the guide star for the Gravity Probe B general relativity experiment. It was chosen for this purpose because its microwave radio emissions are observable with a large radio telescope network on the ground in such a manner that its precise position can be related by interferometry to distant quasars.
The two components of the binary system includes a K-type giant star and a G-type main sequence star. The primary star is estimated to be 1.8 times as massive and 13 times the diameter of the Sun. The secondary star is estimated to be similar to the Sun in size and mass. They orbit their common barycenter in a period precisely estimated to be 24.64877 days.
The variability of IM Pegasi is due to the active chromosphere of the giant primary star, which causes brightness changes of a few tenths of a magnitude as it rotates.


Phi2 Hydrae

Phi2 Hydrae, Latinized from φ2 Hydrae, is a star in the constellation Hydra. It originally received the Flamsteed designation of 1 Crateris before being placed in the Hydra constellation. Based upon an annual parallax shift of 4.31 mas as seen from Earth, it is located roughly 760 light years from the Sun. The star is faintly visible to the naked with an apparent visual magnitude of 6.09. It forms a triangle with the fainter φ1 Hydrae and the brighter φ3 Hydrae, between μ Hydrae and ν Hydrae.
This is an evolved red giant star with a stellar classification of M1 III. It is currently on the asymptotic giant branch, and is a semiregular variable that undergoes changes in luminosity according to three pulsation periods. The star is radiating an estimated 703 times the Sun's luminosity from its photosphere at an effective temperature of 3,791 K.
Phi2 Hydrae has a faint visual companion: a magnitude 12.20 star at an angular separation of 3.50 arc seconds along a position angle of 280°, as of 1959.


LH 95

LH 95 is a modestly sized stellar nursery in the Large Magellanic Cloud. It is related to the HII-region LHA 120-N 64, that is, a region of hydrogen ionized by the bright stars of LH 95.
Previously only young bright stars were known in this stellar association. Imaging using the Hubble Space Telescope, however, allowed the identification of more than 2,500 pre–main sequence stars with masses down to about 0.3 solar masses, thereby giving a detailed picture of what a typical stellar association in the LMC looks like.
The large sample of low-mass pre–main sequence stars, stars that are currently under formation, in LH 95 allows the construction of the first most complete Initial Mass Function of an extragalactic star forming cluster. The Initial Mass Function of LH 95 does not seem to differ from that typical for the Milky Way.


Zeta Caeli

Zeta Caeli, Latinized from ζ Caeli, is an orange-hued star in the constellation Caelum with a visual magnitude of +6.36. It is an evolved K-type giant star and a member of the Milky Way's thick disk population. Based upon an annual parallax shift of 7.59 mas as seen from Earth, this star is located about 430 light years from the Sun.


NGC 7727

NGC 7727 is a peculiar galaxy in the constellation Aquarius.
Features.
This object is located at a distance of 23.3 megaparsecs (76 million light years) of the Milky Way and has a peculiar aspect, with several plumes and streams of irregular shape that explains its inclusion on Halton C. Arp's Atlas of Peculiar Galaxies with the number 222, being classified as a "Galaxy with amorphous spiral arms".
In all likelihood, this system is the product of the merger of two previous spiral galaxies that took place 1 billion years ago, with the aforementioned stellar plumes and streams being the remnants of the disks of the two galaxies that collided to form this object.
Two starlike objects can be seen in NGC 7727's center, at least one of them likely being the former core of one of those two spiral galaxies. In addition to this, 23 objects--candidates to be young globular clusters formed in the collision--can be found in this system.
NGC 7727 is very similar to NGC 7252, another galaxy product of the collision and merging of two former spiral galaxies, in the same constellation. However it has far less gas (neutral hydrogen and molecular hydrogen) than the latter.
NGC 7727's most likely fate is to become an elliptical galaxy in the future, with very little interstellar dust and star formation


Theta Ursae Minoris

Theta Ursae Minoris, Latinized from θ Ursae Minoris, is a suspected binary star system that is visible to the naked eye in the northern circumpolar constellation of Ursa Minor. It is roughly 860 light years from Earth with an apparent visual magnitude of 5.0. The system is moving closer to the Sun with a radial velocity of −25 km/s.
This is a probable spectroscopic binary with two roughly equal components.
 The spectrum matches a stellar classification of K5-III CN0.5, which would normally indicate an evolved, orange-hued giant star of type K that has a mild overabundance of cyanogen in the outer atmosphere. The estimated diameter is around 4.8 times that of the Sun, and it is radiating approximately 1,618 times the Sun's luminosity from an expanded photosphere at an effective temperature of 3,962 K.
Photometry from the Hipparcos satellite mission shows that θ Ursae Minoris varies in brightness by a few hundredths of a magnitude. It is listed as NSV 20342 in the New Catalogue of Suspected Variable Stars.


HD 43587

HD 43587 is a stellar system approximately 63 light-years away in the constellation of Orion, visible to the naked eye. The system comprises four individual stars, with two widely separated binaries forming a quadruple system.
Components.
HD 43587, being a bright, nearby, high proper motion solar-type star, has been fairly extensively studied. The star was found to be slightly hotter than the Sun, but has a similar metallicity and is therefore not much more massive.
Searches for companions to the star, among many other stars, were ongoing throughout the last century. HD 43587 did not seem to have a variable radial velocity or much variability in its astrometry which would indicate that it had a close companion. The Washington Double Star Catalog lists four visual companions; companion B, discovered in 1891, has differing proper motion to the primary, so it is unrelated. Companions C and D, discovered in 1911, have only been observed once, making their relationship uncertain at best. However, Companion E, first observed in 1990, has very similar proper motion to the primary, meaning that it is indeed a companion. Designated HD 43587 B, the star was found to be a faint M-dwarf.
Because of the star's brightness and position in the vicinity of the constellation of Monoceros, HD 43587 A was selected as one of the primary COROT astroseismology targets, which would collect information on the star's internal properties.
Since the primary star is similar to the Sun and did not seem to have a close companion, it was targeted by the radial velocity-based planet searches that began at the end of the twentieth century. In particular, HD 43587 A was observed with the Keck/HIRES spectrograph. However, during 1998 the star's radial velocity was found to decrease by about eight km/s, indicative of a long period stellar companion. An orbital fit found that this new companion has an orbital period of about 30 years, but on a very eccentric path which brings it through periastron in about a year. This third star, designated HD 43587 Ab, was found to have a minimum mass of about
The long period of HD 43587 Ab coupled with the system being close to the Solar System means that the two components of the primary system would be well separated as viewed from Earth, which made it an attractive target for resolving. This was achieved in 2006 with adaptive optics, and has been achieved since with speckle interferometry.
Meanwhile, HD 43587 B became interesting because it was a little-studied, fairly bright M-dwarf. As of such, it was targeted in the STEPS astrometric survey, which found that the star's motion was deviating from linear motion; adaptive optics observations confirmed that HD 43587 B was itself a binary with a fourth component, HD 43587 C. While the orbital period of the binary was too long to constrain the two components' dynamical masses, photometric analysis found that they were both late M-dwarfs.


Rho Serpentis

Rho Serpentis, Latinized from ρ Serpentis, is a single star in the Caput section of the equatorial Serpens constellation. It has an orange hue and is faintly visible to the naked eye with an apparent visual magnitude of +4.78. The distance to this star is approximately 375 light years based on parallax, but it is drifting closer to the Sun with a radial velocity of −62 km/s.
This is an aging giant star with a stellar classification of K4.5III. It is a suspected variable star of unknown type, with an I-band brightness ranging from 3.29 down to 3.44 magnitude. Hipparcos photometry revealed a microvariability with a frequency of 0.17017 cycles per day and an amplitude of 0.0080. With the supply of hydrogen exhausted at its core, it has expanded and now has 48 times the Sun's girth. The star is radiating 492 times the luminosity of the Sun from its swollen photosphere at an effective temperature of 3,930 K.


Beta Librae

Beta Librae (β Librae, abbreviated Beta Lib, β Lib), formally named Zubeneschamali , is (despite its 'beta' designation) the brightest star in the zodiac constellation of Libra. From parallax measurements, its distance can be estimated as from the Sun.
The apparent visual magnitude of this star is 2.6. According to Eratosthenes, Beta Librae was observed to be brighter than Antares. Ptolemy, 350 years later, said it was as bright as Antares. The discrepancy may be due to Antares becoming brighter, but this is not known for certain. It could simply be caused by Beta Librae being a variable star, showing a present-day variability of 0.03 of a magnitude.
Name.
"β Librae" (Latinised to "Beta Librae") is the star's Bayer designation.
It bore the traditional name "Zubeneschamali" (less common renderings, or corruptions, are "Zuben Eschamali", "Zuben el Chamali", "Zubenesch", "Zubenelg"), derived from the Arabic ّالزُبَانَى الشَمَالِي ("al-zubānā al-šamāliyy") meaning "The northern claw". This name originated in a time when Libra was viewed as representing the "claws of the scorpion". There was also "Kiffa Borealis", from the Arabic "al-kiffah aš-šamāliyy" "the northern pan (of the scales)" and the Latin equivalent "Lanx Borealis". 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 "Zubeneschamali" for this star on 21 August 2016 and it is now so entered in the IAU Catalog of Star Names.
In Chinese, (), meaning "Root", refers to an asterism consisting of β Librae, α2 Librae, ι Librae and γ Librae. Consequently, the Chinese name for β Librae itself is (), "the Fourth Star of Root".
Properties.
Based upon the features of its spectrum, Beta Librae has a stellar classification of B8 V, making it a B-type main sequence star. It is about 130 times more luminous than the Sun and has a surface temperature of , double that of the Sun. This high temperature produces light with a simple spectrum, making it ideal for examining the interstellar gas and dust between Earth and the star. Like many stars of its kind, it is spinning rapidly, over 100 times faster than the Sun with a projected rotational velocity of . The measured angular diameter of the primary star is 0.801 mas. At the estimated distance of this system, this yields a physical size of about 4.9 times the radius of the Sun.
This type of massive, hydrogen-fusing star often appears blue-white, and is usually stated to be white or bluish by modern observers, but earlier observers often described Beta Librae as the only greenish star visible to the naked eye. There seems to be no generally accepted explanation for why some observers see it as green. The small periodic variations in the magnitude of Beta Librae suggest the presence of a companion star which is not directly observable from Earth. However, it is categorized as a single star.
References.
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NGC 972

NGC 972 is a dusty spiral galaxy in the northern constellation of Aries, located at an approximate distance of from the Milky Way. It was discovered in 1784 by William Herschel. The galactic features suggest it may have undergone a merger with a gas-rich companion, giving it asymmetrical arms, plus starburst activity in the nucleus and an off-planar nuclear ring. The inner 3.6 kpc of the galaxy is undergoing star formation at the rate of 2.1–2.7 ·yr−1, but it lacks a nuclear bulge.
On October 16, 2008, a possible supernova event was observed about west and north of the galactic center. It reached magnitude 14.7 in the infrared K' band, but only a possible very faint transient event was observed in the visual frequency range, most likely as a result of strong extinction.
The group of galaxies around NGC 972 is sometimes referred to as the "NGC 972 group," which includes NGC 1012, NGC 1056, UGC 1958, UGC 2017, UGC 2053, and UGC 2221.


HD 203949

HD 203949 is a K-type giant star 257 light-years away in the constellation of Microscopium. Its surface temperature is 4618 K. It is either on the red giant branch fusing hydrogen in a shell around a helium core, or more likely a red clump star currently fusing helium in its core. HD 203949 is enriched in heavy elements relative to the Sun, with a metallicity ([Fe/H]) of . As is common for red giants, HD 203949 has an enhanced concentration of sodium and aluminium compared to iron.
Multiplicity surveys did not find any stellar companions around HD 203949 as of 2019.
Planetary system.
In 2014, one planet orbiting HD 203949 was discovered by the radial velocity method. The planet is highly unlikely to have survived the red giant stage of stellar evolution on the present orbit. It is likely to be recently scattered from a wider orbit.
The planetary system configuration is favourable for direct imaging of exoplanets in the near future, and was included in the top ten easiest targets known by 2018.


45 Ophiuchi

45 Ophiuchi is a single star in the equatorial constellation of Ophiuchus, along the southern border with Scorpius. It has the Bayer designation d Ophiuchi, while "45 Ophiuchi" is the Flamsteed designation. In the past it had the designation Theta Telescopii. This object is visible to the naked eye as a faint, yellow-white hued star with an apparent visual magnitude of 4.28. It is located approximately 111.6 light years away from the Sun based on parallax. The star is drifting further from the Earth with a heliocentric radial velocity of +38 km/s.
This object has a stellar classification of F5III-IV, matching an F-type star with a luminosity class displaying mixed traits of a subgiant and a giant star. It is 1.2 billion years old with 1.7 times the mass of the Sun and 3.2 times the Sun's radius. The star is radiating 19 times the luminosity of the Sun from its photosphere at an effective temperature of 6,750 K. It is spinning with a projected rotational velocity of 65 km/s.


Delta Equulei

Delta Equulei, Latinized from δ Equulei, is the second brightest star in the constellation Equuleus. Delta Equulei is a binary star system about 60 light years away, with components of class G0 and F5. Their combined magnitude is 4.47, and their absolute magnitude is 3.142. There is controversy as to the exact masses of the stars. One study puts the larger at 1.22 solar masses and the smaller at 1.17, while another pegs them at 1.66 and 1.593. The luminosity of the larger star is calculated to be 2.23 solar, and the smaller to be 2.17.
System.
William Herschel listed Delta Equulei as a wide binary. Friedrich Georg Wilhelm von Struve later showed this to be an unrelated optical double star. However his son Otto Wilhelm von Struve while making follow-up observations in 1852 found that while the separation of the optical double continued to increase, Delta Equulei itself appeared elongated. He concluded that it is a much more compact binary.


Bond (Chinese constellation)

Leu (or Low) "sieu" () meaning "the Train of a garment", was one of the twenty-eight lunar mansions of the traditional Chinese astronomy. It was one of the White Tiger of the West (西方白虎).


Hen 2-437

Hen 2-437 is a planetary nebula in the constellation Vulpecula. It was first discovered by Rudolph Minkowski in 1946.


V Coronae Australis

V Coronae Australis (V CrA) is a R Coronae Borealis variable star in the constellation Corona Australis. These are extremely hydrogen-deficient supergiants thought to have arisen as the result of the merger of two white dwarfs; fewer than 100 have been discovered as of 2012. V Coronae Australis dimmed in brightness from 1994 to 1998.
It has around 60% the mass of the Sun and an effective (surface) temperature of around 6250 K.


NGC 4605

NGC 4605 is a dwarf barred spiral galaxy in the constellation Ursa Major, located at a distance of from the Milky Way. Physically it is similar in size and in B-band absolute magnitude to the Large Magellanic Cloud. It is a member of the M81 Galaxy Group, along with Messier 81 and Messier 101.


K Carinae

The Bayer designations k Carinae and K Carinae are distinct.


Mu Sagittarii

Mu Sagittarii (μ Sagittarii, abbreviated Mu Sgr, μ Sgr) is a multiple star system in the constellation of Sagittarius. The brightest component, designated Mu Sagittarii Aa, is formally named Polis . The system is 3,000 light-years from the Sun and is part of the Sgr OB1 stellar association.
System.
The components of the Mu Sagittarii system are designated 'A' through 'E', in order of their distance from the brightest, which is Mu Sagittarii A. 'A' is itself a spectroscopic binary with components designated Mu Sagittarii Aa and Ab. Of the five visible stars, component C is considered an optical double, not physically close to the other stars. Component D has also been listed as a purely optical double by some authors, but others consider it to be part of a trapezium system of four gravitationally bound stars (plus an unseen companion).
Nomenclature.
"μ Sagittarii" (Latinised to "Mu Sagittarii") is the system's Bayer designation. The designations of the five constituents as "Mu Sagittarii A", "B", "C", "D" and "E", and those of "A's" components - "Mu Sagittarii Aa" and "Ab" - 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 πολις "polis" in a Coptic manuscript list of lunar stations, all of which Crum concluded were of Greek origin, in this case from "polis" "city".
In 2016, the IAU organized a Working Group on Star Names (WGSN) to catalog 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 "Polis" for the component Mu Sagittarii Aa on 5 September 2017 and it is now so included in the List of IAU-approved Star Names.
In Chinese, (), meaning "Dipper", refers to an asterism consisting of Mu Sagittarii, Phi Sagittarii, Lambda Sagittarii, Sigma Sagittarii, Tau Sagittarii and Zeta Sagittarii. Consequently, the Chinese name for Mu Sagittarii itself is (, .)
Properties.
Variability.
Mu Sagittarii A varies in brightness and is classified as a variable star. The two spectroscopic components eclipse each other with an orbital period of 181 days, causing a 0.08 magnitude drop in brightness (from +3.84 to +3.96). In addition, it shows more irregular variations typical of an Alpha Cygni variable, irregularly pulsating hot supergiant stars.
Physical.
Mu Sagittarii A appears as a type-B giant star with a total luminosity of 180,000 times that of the Sun and a radius of 115 times the Sun's. Its mass is 23 times the solar mass while it has a surface temperature of 11,100 K. Mu Sagitarii Aa is a type B8 supergiant and the companion (Mu Sagitarii Ab) is a type B2 giant.
The remaining components are very weakly bound to the Polis system, and although Mu Sagittarii is visible to the naked eye, the properties of the secondary components are highly uncertain.
The apparent magnitude for component B has been measured at between +8.04 and 10.481, leading to uncertainties about its physical properties, distance, and membership of the system. The Washington Double Star Catalog gives a magnitude of 10.48 and the Catalog of Components of Double and Multiple Stars a magnitude of 11.5.
Component D has an early B spectral type, near B3. The full MK spectral type has been measured as B2 IV, and the assumption of a subgiant luminosity suggests that it is more distant than the other stars of the system. The spectral type has also been estimated photometrically as B2 V, and a main sequence luminosity matches the distance of the other stars.


R Octantis

R Octantis is a Mira variable star located in the southern constellation of Octans. It shines with a luminosity 9304 times that of the Sun and has a surface temperature of 2571 K.


NGC 5643

NGC 5643 is an intermediate spiral galaxy in constellation Lupus. It is located at a distance of circa 60 million light years from Earth, which, given its apparent dimensions, means that NGC 5643 is about 100,000 light years across. NGC 5643 has an active galactic nucleus and is a type II Seyfert galaxy.
Observation history.
The galaxy was first reported by James Dunlop on May 10, 1826 with his 9-inch reflector telescope and described it as exceedingly faint. The galaxy was also spotted by John Herschel and added it in the "General Catalogue of Nebulae and Clusters" as number 3572. The galaxy is located only 15 degrees from the galactic plane.
Structure.
NGC 5643 is a grand design spiral galaxy, with two well-defined, symmetric arms. In the circumnuclear region are present and other dust spirals, but the two main dust arms are wider. The galaxy is seen nearly face on, at an inclination of ∼ 27°.
Active galactic nucleus.
The galaxy has a low-luminosity active galactic nucleus of Seyfert 2 type and is also a luminous infrared galaxy. The galaxy has a double sided diffuse radiojet. The galaxy exhibits an extended emission line region elongated in a direction close to the radio position angle of 87°±3°. Chris Simpson et al. analysed images takes from WFPC2 camera of the Hubble Space Telescope in [O III] λ5007 and Hα and found emission extending eastward for at least 1.8 kpc and in the [O III]/Hα map a well-defined V-shaped structure that they identified as the projection of a tridimensional ionisation cone, which shares the same axis with the radio emission. A dust lanes perpendicular to this axis obstructs the nucleus from direct view. A disk of material was found when the data cubes of VLT were analysed. It is aligned with the nucleus and circles it and it possibly provides gas to the active galactic nucleus. The mass of the supermassive black hole has been estimated based on the galaxy stellar velocity dispersion to be 106.4 M⊙. It has been proposed that the gas outflow has led to star formation on two locations on the bar of the galaxy which lie at the location where the gas from the nucleus encounters the dense material of the bar.
Via observations of the galaxy from XMM Newton telescope in 2009, the galaxy is found to be a Compton–thick active galactic nucleus. Also the galaxy emits soft X-rays, mainly from photoionized matter. The prensence of the compton-thick column which obstructs the nucleus was confirmed from observations by NuSTAR.
Ultraluminous X-ray source.
In 2004, Guainazzi et al. detected in the images from XMM-Newton an ultraluminous X-ray source, named NGC 5643 ULX1, located within 0.8 arcminutes from the nucleus. The source outshone the nucleus in X-rays and if it is located within NGC 5643 its luminosity is over 1040 erg/s. Its luminosity is variable. The X-rays could be produced either by an advection dominated disc or a Comptonising corona and the X-ray source considered to be a black hole of stellar origin of approximately 30 solar masses.
Supernovae.
NGC 5643 has been home of two supernovae, SN 2013aa and SN 2017cbv. SN 2013aa was discovered by Stuart Parker from New Zealand on a 30-s unfiltered CCD image taken on 13.621 UT February 2013, as part of the Backyard Observatory Supernova Search, at magnitude 11.9. It was classified as a Type Ia a few days before maximum brightness.
SN 2017cbv was discovered on March 10, 2017 by the Swope 1-m telescope at Las Campanas Observatory and was classified as a very young Ia supernova. It increased in magnitude from 15.8 to 14.8 within the next day.
Nearby galaxies.
NGC 5643 has a satellite dwarf galaxy, ESO 273-014. NGC 5643 is the foremost member of a small galaxy group that also includes NGC 5530.


47 Tauri

47 Tauri (abbreviated to 47 Tau) is a binary star in the zodiac constellation of Taurus. Parallax measurements made by the Hipparcos spacecraft put it at a distance of about 330 light-years (102 parsecs) from Earth. The system has a combined apparent magnitude of about 4.89, meaning it can be faintly seen with the naked eye, according to the Bortle scale.
47 Tauri is a visual binary, meaning that the two components can be resolved, and the orbit is derived from the positions of the two stars. The primary component is a G-type giant. Its radius is about 13 times that of the Sun. The companion is likely a white-colored A-type main-sequence star that is fainter. The two stars are separated about 1.3 arcseconds away, and because of their large separation, the two stars take some 479 years to complete an orbit.


List of stars in Delphinus

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


NGC 4694

NGC 4694 is a lenticular galaxy in the constellation Virgo. It was discovered by William Herschel on March 15, 1784


Delta Leporis

Delta Leporis (δ Leporis) is a solitary, orange-hued star in the southern constellation of Lepus. It is visible to the naked eye with an apparent visual magnitude of 3.85. Based upon an annual parallax shift of 28.68 mas, it is 114 light years distant from Earth.
This is an old, evolved K-type star with an age of about 10.7 billion years. Keenan and McNeil (1989) classified it as , indicating it is a giant star showing a deficiency of iron and an excess of cyanogen in its atmosphere. However, Gray et al. (2006) listed it as , which would suggest a less evolved subgiant star. It may be a red clump star, which indicates it is generating energy through helium fusion at its core.
The measured angular diameter of this star, after correction for limb darkening, is . At the estimated distance of this star, this yields a physical size of about 10 times the radius of the Sun. It has only 94% of the Sun's mass and is radiating 46 times the Sun's luminosity from its photosphere at an effective temperature of 4,660 K.
References.
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Telescopium Herschelii

Telescopium Herschelii (Latin for "Herschel's telescope"), also formerly known as Tubus Hershelli Major, is a former constellation in the northern celestial hemisphere. Maximilian Hell established it in 1789 to honour Sir William Herschel's discovery of the planet Uranus. It fell out of use by the end of the 19th century. Psi2 Aurigae at apparent magnitude 4.8 was the constellation's brightest star.
History.
It was one of two constellations created by Maximilian Hell in 1789 to honour the famous English astronomer Sir William Herschel's discovery of the planet Uranus. Named "Tubus Hershelli Major" by Hell, it was located in the constellation Auriga near the border to Lynx and Gemini and depicted Herschel's 20-ft-long telescope. Its sibling was Tubus Hershelli Minor, which lay between Orion and Taurus. The two telescopes lay near Zeta Tauri, near where the planet Uranus was first spotted.
Johann Elert Bode renamed the constellation "Telescopium Herschelii" and omitted the smaller telescope constellation in his 1801 "Uranographia" star atlas. In his atlas, the constellation depicted Herschel's earlier 7-foot telescope. It was ignored by some celestial cartographers such as Argelander in 1843, Proctor in 1876, Rosser in 1879 and Pritchard in 1885, yet did appear in two works of the 1890s. However, it was noted by Allen in 1899 that it was becoming obsolete. In 1930, when the official borders of the constellations were drawn up, its stars were absorbed into Auriga, Gemini and Lynx.
Notable features.
Psi2 Aurigae (also known as 50 Aurigae), with an apparent magnitude of 4.8, was the brightest star in the constellation, Bode assigning it the designation 'a'. Located 420 ± 20 light-years distant from earth, it is an orange giant of spectral type K3III. Other stars belonging to the constellation include Psi4, Psi5, Psi7, 63, 64, 65 and 66 Aurigae, and Omicron Geminorum.
Thought to be around 4 billion years old, Psi5 Aurigae is a sunlike star of spectral type G0V that is around 1.07 times as massive as the Sun and 1.18 times as wide. It appears to have a circumstellar disk of dust, known as a debris disk.


28 Cygni

28 Cygni is a single star in the northern constellation of Cygnus. It is a faint blue-white hued star but visible to the naked eye with an apparent visual magnitude of 4.93. The distance to 28 Cyg, as estimated from its annual parallax shift of , is around 620 light years. It has an absolute magnitude of −2.56, which means that if the star were just away it would be brighter than Sirius, the brightest star in the night sky.
This is a B-type main-sequence star with a stellar classification of B2.5 V, per Lesh (1968). Slettebak (1982) found a class of B2 IV(e), which would suggest this is a more evolved subgiant star. It is a Be star, which means the spectrum displays emission lines due a disk of ejected gas in a Keplerian orbit around the star. The star displays short-term variability with two or more periods, and is classified as an SX Arietis variable by Samus et al. (2017). It is spinning rapidly with a projected rotational velocity of 320 km/s; estimated at round 80% of the critical rotation rate. This is giving the star an oblate shape with an equatorial bulge out to 6.5 times the Sun's radius, compared to 5.7 at the poles.


NGC 7822

NGC 7822 is a young star forming complex in the constellation of Cepheus. The complex encompasses the emission region designated Sharpless 171, and the young cluster of stars named Berkeley 59. The complex is believed to be some 800–1000 pc distant, with the younger components aged no more than a few million years. The complex also includes one of the hottest stars discovered within 1 kpc of the Sun, namely BD+66 1673, which is an eclipsing binary system consisting of an O5V that exhibits a surface temperature of nearly 45,000 K and a luminosity about 100,000 times that of the Sun. The star is one of the primary sources illuminating the nebula and shaping the complex's famed pillars of creation-type formations, the "elephant trunks".
In popular culture.
The NGC 7822 cluster features prominently in Frontier Development's Elite Dangerous, where it contains a large number of fictional stellar black holes.


75 Tauri

75 Tauri is a single, orange-hued star in the zodiac of constellation Taurus. It is a dim star but visible to the naked eye with an apparent visual magnitude of 4.96. Based upon an annual parallax shift of 17.47 mas as seen from Earth's orbit, it is located around 187 light years away. Due to its position near the ecliptic, it is subject to lunar occultations. The star is moving further from the Sun with a heliocentric radial velocity of +16 km/s.
The stellar classification of 75 Tauri is K1 IIIb, indicating it is an aging giant star that has exhausted the supply of hydrogen at its core. At the estimated age of roughly 2.7 billion years, this has become a red clump star that is generating energy through helium fusion in its core region. The star has 1.5 times the mass of the Sun and has expanded to 11 times the Sun's radius. It is radiating 41 times the Sun's luminosity from its enlarged photosphere at an effective temperature of around 4,697 K.


42 Herculis

42 Herculis is a single star located around 450 light years away from the Sun in the northern constellation of Hercules. It is visible to the naked eye as a faint, red-hued star with an apparent visual magnitude of 4.86. The star is moving closer to the Earth with a heliocentric radial velocity of −56 km/s.
This is an aging red giant star on the asymptotic giant branch with a stellar classification of M2.5III. It has been catalogued as a suspected variable star, although a 1992 photometric survey found the brightness to be constant. Having exhausted the supply of hydrogen at its core, the star has expanded to 64 times the Sun's radius. It is radiating 734 times the luminosity of the Sun from its swollen photosphere at an effective temperature of 3761 K.
There is an unknown source of X-ray and far ultraviolet emission originating from a location offset by more than one arcsecond from the star. This may indicate there is an undetected main sequence companion.


Nu Coronae Borealis

The Bayer designation ν Coronae Borealis (Nu Coronae Borealis) is an optical pair of stars in the constellation Corona Borealis:
As of 2011, the pair had an angular separation of along a position angle of 164°.


45 Aquilae

45 Aquilae, abbreviated 45 Aql, is a triple star system in the equatorial constellation of Aquila. "45 Aquilae" is its Flamsteed designation. It is located away from Earth, give or take a 6 light-year margin of error, and has a combined apparent visual magnitude of 5.7. The system is moving closer to the Earth with a heliocentric radial velocity of -46 km/s.
Based upon a stellar classification of A3 IV, the primary component of this system is a subgiant star that is in the process of evolving away from the main sequence. The star has 2.6 times the mass of the Sun and is spinning with a projected rotational velocity of 75 km/s. It has an orbiting companion with a period of 20.31 years and an eccentricity of 0.054. At an angular separation of 42.2 arcseconds from this pair is a 12.7 magnitude tertiary companion.


Alpha Horologii

Alpha Horologii (α Horologii) is a solitary orange-hued giant star in the constellation Horologium. It is visible to the naked eye with an apparent visual magnitude of +3.85. Based upon an annual parallax shift of 28.36 mas as seen from the Earth, it is located from the Sun. The star is moving away from the Sun with a radial velocity of +21.6 km/s.
The stellar classification of K2 III indicates this is an evolved giant star of the K class. This means it has consumed the hydrogen at its core and has migrated away from the main sequence, with its outer envelope cooling and expanding in the process. Alpha Horologii has an estimated 1.55 times the mass of the Sun and is radiating 38 times the Sun's luminosity from its photosphere at an effective temperature of 5,028 K. It has swollen to around 11 times the diameter of the Sun, having spent much of its life as a white main sequence star.


44 Ophiuchi

44 Ophiuchi is a single star in the constellation Ophiuchus. It has the Bayer designation b Ophiuchi, while "44 Ophiuchi" is the Flamsteed designation. It is visible to the naked eye as a faint, white-hued star with an apparent visual magnitude of 4.16. The distance to this object is approximately 83.2 light years based on parallax. It is drifting closer to the Earth with a heliocentric radial velocity of -37.2 km/s, and is predicted to come within around 585,000 years from now.
This is an Am star with a stellar classification of kA5hA9mF1III, indicating it has the luminosity class of a giant star with a spectrum that matches an A5 star based on the calcium K line, and an A9 star from the hydrogen and metal lines. It is around a billion years old with 1.77 times the mass of the Sun and 1.9 times the Sun's girth. The star is radiating 13 times the Sun's luminosity from its photosphere at an effective temperature of 7,559 K. It retains a moderately high rotation rate, showing a projected rotational velocity of 78 km/s.


Alicante 8

Alicante 8, also known as RSGC4, is a young massive open cluster belonging to the Milky Way galaxy. It was discovered in 2010 in the 2MASS survey data. As of 2010, the only members of the cluster that are currently identified are 8–13 red supergiants—young massive stars undergoing helium burning in their cores. The cluster is located in the constellation Scutum at the distance of about from the Sun. It is likely situated at the intersection of the northern end of the Long Bar of the Milky Way and the inner portion of the Scutum–Centaurus Arm—one of the two major spiral arms.
The age of Alicante 8 is estimated to be around 16–20 million years. The observed red supergiants are type II supernova progenitors. The cluster is heavily obscured and have not been detected in the visible light. It lies close to other groupings of red supergiants known as RSGC1, Stephenson 2, RSGC3, Alicante 7, and Alicante 10. The mass of the open cluster is estimated at 10–20 thousand solar masses, which makes it one of the most massive open clusters in the Galaxy.


Theta Piscis Austrini

Theta Piscis Austrini (θ Piscis Austrini) is a binary star system in the southern constellation of Piscis Austrinus. It is faintly visible to the naked eye with a combined apparent visual magnitude of +5.01. Based upon an annual parallax shift of 10.16 mas as seen from the Earth, the system is located around 320 light years from the Sun.
The binary nature of this system was discovered in 1951 by South African astronomer W. S. Finsen. Both components A and B have the same apparent magnitude. They orbit each other with a period of 20 years and an eccentricity of 0.256. The pair are A-type main sequence stars with stellar classifications of A1 V. A magnitude 11.3 star, labelled component C, is located at an angular separation of 33.2 arc seconds along a position angle of 342°, as of 1999.
Theta Piscis Austrini is moving through the Galaxy at a speed of 21.3 km/s relative to the Sun. Its projected Galactic orbit carries it between 22,600 and 38,300 light years from the center of the Galaxy. Theta Piscis Austrini came closest to the Sun 2.7 million years ago when it had brightened to magnitude 4.54 from a distance of 256 light years.
Naming.
In Chinese, (), meaning "Celestial Money", refers to an asterism consisting of refers to an asterism consisting of θ Piscis Austrini, 13 Piscis Austrini, ι Piscis Austrini, μ Piscis Austrini and τ Piscis Austrini. Consequently, the Chinese name for θ Piscis Austrini itself is (, .)


Iota Mensae

Iota Mensae is a single star about away in the faint constellation Mensa. It has a very slightly variable apparent magnitude of 6.0, making it visible with the naked eye under good skies.
Iota Mensae has a spectral type of B8III, indicating that it has exhausted hydrogen at its core and expanded away from the main sequence. It is about 3.7 times the mass (), 52 times as luminous, and has swollen to 2.9 times the radius of the Sun (). It is calculated to be 314 million years old. It has been catalogued as a chemically peculiar star with abnormally strong lines of silicon in its spectrum but this classification is now considered doubtful. Its brightness varies by a few hundredths of a magnitude. Its period was initially measured at 2.6 days, but this is now considered to be a period of 5.3 days with primary and secondary minima of a similar depth. The variability is thought to be due to the rotation of the star.


Theta Lyrae

Theta Lyrae (θ Lyr) is a star in a trinary star system, in the constellation Lyra, approximately 770 light years away from Earth. Theta Lyrae is an orange bright giant star of the spectral type K0II, which means that it possesses a surface temperature of about 5,000 kelvins, and is many times bigger and brighter, yet cooler, than the Sun.
It is orbited by a subsystem composed of BD+37° 3399 and BD+37° 3399B. 10th magnitude BD+37° 3399 is a giant star with a spectral type of K2III. It is therefore almost the same temperature as Theta Lyrae, but smaller and dimmer. BD+37° 3399B is an 11th magnitude star of an unknown spectral type.


List of stars in Lupus

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


Nu Tauri

ν Tauri, Latinized as Nu Tauri, is a single star in the zodiac constellation of Taurus. It is a white-hued star and is visible to the naked eye with an apparent visual magnitude of +3.91. This object is located 117 light years from the Sun based on parallax, but is drifting closer with a radial velocity of −6 km/s. It is predicted to come to within roughly of the Sun in around five million years.
This object is an A-type main-sequence star with a stellar classification of A0.5Va. It is 206 million years old and is rotating with a projected rotational velocity of 83 km/s. The star has 2.25 times the mass of the Sun and 2.87 times the Sun's radius. It is radiating 28 times the luminosity of the Sun from its photosphere at an effective temperature of 7,836 K.
Nu Tauri has a magnitude 9.21 visual companion at an angular separation .


HD 20367

HD 20367 is a star in the constellation of Aries, close to the border with the Perseus constellation. It is a yellow-white hued star that is a challenge to view with the naked eye, having an apparent visual magnitude of 6.40. Based upon parallax measurements, it is located 85 light years from the Sun. It is drifting further away with a radial velocity of +6.4 km/s. Based upon its movement through space, it is a candidate member of the Ursa Major Moving Group of co-moving stars that probably share a common origin.
This object is a late F-type main-sequence star with a stellar classification of F8V. It is about three billion years old and is spinning with a projected rotational velocity of 5.5 km/s. The star is 12% larger and 13% more massive than the Sun. It is radiating 1.58 times the luminosity of the Sun from its photosphere at an effective temperature of 6,100 K.
Candidate planetary system.
In June 2002, an announcement was made that a Jupiter-mass or larger extrasolar planet had been found orbiting the star, with a period of and an eccentricity of 0.32. The eccentric nature of this planet's orbit meant that it spends part of each circuit around the star outside the habitable zone. However, subsequent observations put the existence of this planet in doubt.


69 Orionis

69 Orionis is a single star in the equatorial constellation of Orion, positioned a couple of degrees to the north of Xi Orionis. It has the Bayer designation f1 Orionis; "69 Orionis" is the Flamsteed designation. The star is visible to the naked eye as faint, blue-white hued point of light with an apparent visual magnitude of 4.92. It is located approximately 530 light years from the Sun based on parallax, and is drifting further away with a radial velocity of +22 km/s. In 2015, H. Bouy and J. Alves suggested that it is a member of the newly-discovered Taurion OB association.
This object is a B-type main-sequence star with a stellar classification of B5Vn, where the 'n' suffix indicates "nebulous" (broad) lines due to rapid rotation. It has a projected rotational velocity of 285 km/s, compared to a critical velocity of ; the polar axis is inclined by . This is a known Be star that began behaving as a normal star in November, 1982. It has 6.4 times the mass of the Sun and is radiating around 1442 times the Sun's luminosity from its photosphere at an effective temperature of 17,090 K.


NGC 3504

NGC 3504 is a barred spiral galaxy in the constellation Leo Minor.
There is a large amount of molecular gas centered on the galactic nuculeus. Compared with other barred spiral galaxies, NGC 3504 is in an early phase of its evolution.
The mass of NGC 3504 has been difficult to narrow down, but it is believed to be between 2.5*109 M⊙ and 9*109 M⊙.


List of stars in Corona Borealis

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


WASP-59

WASP-59 is a K-type main-sequence star about 379 light-years away. The star's age is essentially unconstrained by observations. WASP-59 is slightly depleted in heavy elements, having 70% of the solar abundance of iron. The star produces extremely low levels of ultraviolet light, indicating an absence of flare activity.
A multiplicity survey in 2015 did not detect any stellar companions to WASP-59.
Planetary system.
In 2012 a transiting hot Jupiter planet b was detected on a tight, mildly eccentric orbit.
Its equilibrium temperature is . The planet is unusually dense for a gas giant, representing an outlier on a mass-radius diagram.


HD 38529

HD 38529 (138 G. Orionis) is a binary star approximately 138 light-years away in the constellation of Orion.
HD 38529 A.
HD 38529 A is a yellow subgiant star, which has also been classified as a main sequence dwarf of spectral type G4V. It is about 40% more massive than our Sun. Two substellar companions are known in orbit around this star, including one with a mass above the deuterium fusion limit that is often used as the dividing line between giant planets and brown dwarfs. There is a debris disk located at least 86 astronomical units from the star. Its orbit is probably mildly misaligned with planetary orbits, by 21−45°.
Planetary system.
In 2002, the planet HD 38529 b was discovered orbiting the star HD 38529 A by Debra Fischer and collaborators who detected it using the doppler spectroscopy technique. It has mass 78% that of Jupiter and orbits very close to the star, just beyond the distance limit for hot Jupiters. One year later, a massive superjovian HD 38529 c was found orbiting at 3.68 AU with a minimum mass of 12.7 Jupiter masses. Astrometric measurements from the Hipparcos satellite gave a best fit inclination of 160° and a true mass 37 times that of Jupiter, turning this planet into a brown dwarf. Further study of the system using Hubble Space Telescope astrometry revised the mass of HD 38529 c downwards to 17.7 Jupiter masses and suggested the presence of an additional planet, orbiting in the gap between HD 38529 b and c. The possible third planet was refuted after additional radial velocity measurements were collected.
HD 38529 B.
HD 38529 B is a common proper motion stellar companion to HD 38529 A at a projected distance of about ~12000 Astronomical units. The star is a red dwarf of spectral type M3.0V. Wide binary stars such as HD 38529 AB have been shown to be vulnerable to disruption by galactic tides and perturbations by passing stars.


S Canis Minoris

S Canis Minoris is a variable star in the equatorial constellation Canis Minor. It has a peak apparent visual magnitude of , which lies below the minimum brightness that is normally visible to the naked eye. The star is located at a distance of approximately 1,600 light-years from the Sun based on stellar parallax, and is drifting further away with a radial velocity of about +68 km/s.
This is an aging red giant star with a stellar classification of M7-8e, where the 'e' suffix indicates emission lines in the spectrum. It is a Mira-type long period variable that varies by an amplitude of 4.27 in visual magnitude over a period of . Evidence has been found of asymmetry in this star, suggesting a non-spherical shape. Abundance-wise, it is an oxygen-rich giant and the emission feature is of the oxygen-rich silicate class as it sheds silicate dust from its atmosphere. The star is shedding mass at the rate of ·yr−1.


Willow (Chinese constellation)

The Willow mansion (柳宿, pinyin: Liǔ Xiù) is one of the Twenty-eight mansions of the Chinese constellations. It is one of the southern mansions of the Vermilion Bird.


Upsilon Draconis

Upsilon Draconis (υ Dra) is a binary star system in the northern circumpolar constellation of Draco. It is faintly visible to the naked eye with an apparent visual magnitude of 4.83. Based upon an annual parallax shift of 9.48 mas as measured from Earth, it is located around 340 light years from the Sun. At that distance, the visual magnitude of the star is diminished by an extinction factor of 0.02 due to interstellar dust.
In Chinese, (), meaning "Left Wall of Purple Forbidden Enclosure", refers to an asterism consisting of υ Draconis, ι Draconis, η Draconis, ζ Draconis, θ Draconis, 73 Draconis, γ Cephei and 23 Cassiopeiae.
This is a single-lined spectroscopic binary star system with an orbital period of 258.48 days and an eccentricity of 0.21. The primary, component A, is an evolved K-type giant star with a stellar classification of K0 III. It is a suspected barium star, which may indicate the orbiting companion, component B, is a white dwarf star.
The measured angular diameter of the primary, after correction for limb darkening, is . At the estimated distance of Upsilon Draconis, this yields a physical size of about 19 times the Sun's radius. It is about 1.37 billion years old with an estimated 2.05 times the mass of the Sun. The star is radiating 2.23 times the solar luminosity from its photosphere at an effective temperature of 4,561 K.
References.
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NGC 670

NGC 670 is a lenticular galaxy located in the Triangulum constellation about 165 million light years from the Milky Way. It was discovered by the German-British astronomer William Herschel in 1786.


NGC 255

NGC 255 is a barred spiral galaxy in the constellation Cetus. It was discovered on November 27, 1785, by Frederick William Herschel.


EF Eridani

EF Eridani (abbreviated EF Eri, sometimes incorrectly referred to as EF Eridanus) is a variable star of the type known as polars, AM Herculis stars, or magnetic cataclysmic variable stars. Historically it has varied between apparent magnitudes 14.5 and 17.3, although since 1995 it has generally remained at the lower limit. The star system consists of a white dwarf with a substellar-mass former star in orbit.
EF Eridani B.
The substellar mass in orbit around the white dwarf is a star that lost all of its gas to the white dwarf. What remains is an object with a mass of 0.05 solar masses (), which is too small to continue fusion, and does not have the composition of a super-planet, brown dwarf, or white dwarf. There is no category for such a stellar remnant.
It is theorized that 500 million years ago, the white dwarf started to cannibalize its partner, when they were separated by 7 million km. As it lost mass, the regular star spiralled inward, until now they are separated by a mere 700,000 km.
Another former star orbits the pulsar PSR J1719-1438.


NGC 6845

NGC 6845 (also known as Klemola 30) is an interacting system of four galaxies in the constellation Telescopium. The cluster has certain similarities with Stephan's Quintet. Its distance is estimated to be about 90 Mpc.
The components of the galaxy cluster are the two spiral galaxies NGC 6845A and NGC 6845B as well as the two lenticular galaxies NGC 6845C and NGC 6845D. The four galaxies occupy an area of about 4' x 2' in the sky. The largest galaxy in this compact galaxy cluster is NGC 6845A, a barred spiral galaxy. SN 2008DA was a Type II supernova observed in NGC 6845A in June 2008. The dwarf galaxy ATCA J2001-4659, which is found around 4.4' northeast of NGC 6845B, was identified as a companion of NGC 6845.
NGC 6845 was discovered on July 7, 1834 by John Herschel.


HD 90853

HD 90853 is a single star in the southern constellation Carina. It has the Bayer designation "s Carinae", while "HD 98053" is the identifier from the "Henry Draper catalogue". This is a variable star with an apparent visual magnitude that ranges from 3.36 down to 3.51, and thus is bright enough to be visible to the naked eye. It is located at a distance of approximately 1,340 light years from the Sun based on parallax, and has an absolute magnitude of −4.44. The star is drifting further away with a radial velocity of +9 km/s.
This is an aging bright giant or supergiant star that has been assigned stellar classifications of F2II and F0Ib, respectively. It has seven times the mass of the Sun and has expanded to 45 times the Sun's radius. It is spinning with a projected rotational velocity of 22 km/s. The star is radiating 3,466 times the luminosity of the Sun from its enlarged photosphere at an effective temperature of 6,598 K.


HD 75289

HD 75289 is a faint double star in the southern constellation of Vela. The primary component has a yellow hue and an apparent visual magnitude of 6.35. Under exceptionally good circumstances it might be visible to the unaided eye; however, usually binoculars are needed. The pair are located at a distance of 95 light years from the Sun based on parallax, and are drifting further away with a radial velocity of +10 km/s.
The brighter member, component A, is a G-type main-sequence star like the Sun with a stellar classification of G0V. In 1982 it was classified as a supergiant, but this proved erroneous. It has an age comparable to the Sun and is considered metal-rich, with a greater abundance of heavier elements compared to the Sun. The star has 14% more mass than the Sun and a 30% greater girth. It is spinning with a projected rotational velocity of 3 km/s, giving it a ~16 day rotation period. The star is radiating double the luminosity of the Sun from its photosphere at an effective temperature of 6,184 K.
In 2004, a co-moving stellar companion was identified, based on an earlier suggestion from 2001. Designated component B, this red dwarf star lies at an angular separation of , corresponding to a projected separation of . However, the radial distance between the stars is unknown, so they are probably further apart. In any case, one revolution around the primary would take thousands of years to complete. The study that found the red dwarf also rules out any further stellar companions beyond 140 AU and massive brown dwarf companions from 400 AU up to 2,000 AU.
Planetary system.
In 1999 a exoplanet HD 75289 b with half the mass of Jupiter was detected orbiting the primary by radial velocity method. This exoplanet is a typical hot Jupiter that takes only about 3.51 days to revolve at an orbital distance of 0.0482 AU.


NGC 234

NGC 234 is a spiral galaxy located in the constellation Pisces. It was discovered on October 14, 1784 by William Herschel.


Kappa Pyxidis

Kappa Pyxidis, Latinized from κ Pyxidis, is a single, orange-hued star in the southern constellation of Pyxis. It is visible to the naked eye as a faint point of light with an apparent visual magnitude of +4.62. The star is located approximately 520 light years from the Sun based on parallax, but is drifting closer with a radial velocity of −45 km/s and may come as close as in around 2.6 million years. It is moving through space at the rate of 53.7 km/s relative to the Sun and is following an orbit through the Milky Way galaxy with a large eccentricity of 0.68
This is an aging giant with a stellar classification of K4III, having exhausted the supply of hydrogen at its core then expanded and cooled. At present it has 67 times the radius of the Sun. It is a variable star of uncertain type, changing brightness with an amplitude of 0.0058 in visual magnitude over a period of 8.5 days. The star radiates 927 times the luminosity of the Sun from its bloated photosphere at an effective temperature of 3,931 K. A magnitude 10 visual companion is located at an angular separation of .


Kappa Lupi

The Bayer designation κ Lupi (Kappa Lupi) is shared by two star systems in the constellation Lupus:
According to Eggleton and Tokovinin (2008), the pair form a binary system with an angular separation of .


N Velorum

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


S Carinae

The Bayer designations S Carinae and s Carinae are distinct. Due to technical limitations, both designations link here. For the star


NGC 4260

NGC 4260 is a barred spiral galaxy in the constellation Virgo. It was discovered by William Herschel on April 13, 1784.


XX Pyxidis

XX Pyxidis is a star located in the constellation Pyxis. It is one of the more-studied members of a class of stars known as Delta Scuti variables—short period (six hours at most) pulsating stars that have been used as standard candles and as subjects to study astroseismology. Astronomers made more sense of its pulsations when it became clear that it is also a binary star system. The main star is a white main sequence star of spectral type A4V that is around 1.85 times as massive as the Sun. Its companion is most likely a red dwarf star of spectral type M3V, around 0.3 times as massive as the Sun. The two are very close—possibly only 3 times the diameter of the Sun between them—and orbit each other every 1.15 days. The brighter star is deformed into an egg-shape, and pulsates in several overlapping modes 26-76 times per day.


V352 Aurigae

V352 Aurigae is a variable star in the northern constellation of Auriga. It dimly visible to the naked eye with an apparent visual magnitude that ranges from 6.13 down to 6.18. According to the Bortle scale, it is faintly visible to the naked eye from dark rural skies. The star is located at a distance of approximately 970 light years from the Sun based on parallax, but is drifting closer with a radial velocity of −7 km/s.
The stellar classification of this star is A9III, which matches an A-type star with the luminosity class of an evolved giant star. It is listed as a spectral standard for stars of that class, although other researchers have classed it as F0II-III or F1IV.
V352 Aurigae is a low amplitude Delta Scuti variable with a period of , which means the variability is caused by the rotation of the host star in combination with localized regions of activity. The star has 13 times the radius of the Sun and is radiating 242 times the Sun's luminosity from its photosphere at an effective temperature of 6,350 K. It is unusually luminous for a Delta Scuti variable. It is also suspected of being a chemically peculiar star of the Delta Delphini type, although the anomalies are not pronounced.


Sigma Ophiuchi

Sigma Ophiuchi, Latinized from σ Ophiuchi, is a single, orange-hued star in the equatorial constellation Ophiuchus. Its apparent visual magnitude is 4.31, which is bright enough to be faintly visible to the naked eye. The annual parallax shift of 3.62 mas as seen from Earth provides a distance estimate of roughly 900 light years. It is moving closer to the Sun with a radial velocity of −28 km/s.
This is an evolved giant star of type K with a stellar classification of K2 III. Wittkowski et al. (2017) consider it to have a luminosity class of II-III, suggesting it is in a transitional zone between giants and supergiant stars. It has around 5 times the mass of the Sun and 73 times the Sun's radius. The star is radiating 2,047 times the Sun's luminosity from its enlarged photosphere at an effective temperature of 4,540 K.


Xi Eridani

ξ Eridani (Latinised as Xi Eridani) is a solitary star in the constellation Eridanus. With an apparent visual magnitude of 5.17, it is faintly visible to the naked eye on a clear, dark night. Based upon an annual parallax shift of 0.00156 arcseconds, it is located around 209 light years from the Sun. The star is considered a member of the Sirius supercluster.
This is an ordinary A-type main sequence star with a stellar classification of A2 V, indicating that it is generating energy through the thermonuclear fusion of hydrogen into helium in its core region. It is around 450 million years old and has a relatively high rate of rotation with a projected rotational velocity of 194 km/s. The star has about 2.3 times the mass of the Sun, 2.2 times the Sun's radius, and radiates 27.6 times the solar luminosity from its outer atmosphere at an effective temperature of 8,400 K.


Barnard 68

Barnard 68 is a molecular cloud, dark absorption nebula or Bok globule, towards the southern constellation Ophiuchus and well within our own galaxy at a distance of about 400 light-years, so close that not a single star can be seen between it and the Sun. American astronomer Edward Emerson Barnard added this nebula to his catalog of dark nebulae in 1919. His catalog was published in 1927, at which stage it included some 350 objects. Because of its opacity, its interior is extremely cold, its temperature being about 16 K (−257 °C/-431 °F). Its mass is about twice that of the Sun and it measures about half a light-year across.
Characteristics.
Despite being opaque at visible-light wavelengths, use of the Very Large Telescope at Cerro Paranal has revealed the presence of about 3,700 blocked background Milky Way stars, some 1,000 of which are visible at infrared wavelengths. Careful measurements of the degree of obscuration resulted in a finely sampled and accurate mapping of the dust distribution inside the cloud. Observations obtained with Herschel Space Observatory were able to constrain the distribution of the dust component and its temperature even more. Having a dark cloud in the solar neighborhood greatly facilitates observation and measurement. If not disrupted by external forces, the stability of dust clouds is a fine balance between outward pressure caused by the heat or pressure of the cloud's contents, and inward gravitational forces generated by the same particles (see Jeans instability and Bonnor-Ebert mass). This causes the cloud to wobble or oscillate in a manner not unlike that of a large soap bubble or a water-filled balloon which is jiggled. In order for the cloud to become a star, gravity must gain the upper hand long enough to cause the cloud to collapse and reach a temperature and density where fusion can be sustained. When this happens, the much smaller size of the star's envelope signals a new balance between greatly increased gravity and radiation pressure.
The cloud's mass is about twice that of the Sun, and it measures about half a light-year across. Barnard 68's well-defined edges and other features show that it is on the verge of gravitational collapse followed by becoming a star within the next 200,000 years or so.
The cloud is often confused with Boötes void although the two have nothing in common, but pictures of Barnard 68 are often used to illustrate articles about Boötes void.


NGC 890

NGC 890 is a lenticular galaxy in the constellation Triangulum. It is estimated to be 180 million light-years from the Milky Way and has a diameter of approximately 130,000 ly. NGC 890 was discovered on September 13, 1784 by Wilhelm Herschel.


GD 358

GD 358 is a variable white dwarf star of the DBV type. Like other pulsating white dwarfs, its variability arises from non-radial gravity wave pulsations within itself. GD 358 was discovered during the 1958–1970 Lowell Observatory survey for high proper motion stars in the Northern Hemisphere. Although it did not have high proper motion, it was noticed that it was a very blue star, and hence might be a white dwarf. Greenstein confirmed this in 1969.
In 1968, Arlo U. Landolt discovered the first intrinsically variable white dwarf when he found that HL Tau 76 varied in brightness with a period of approximately 749.5 seconds, or 12.5 minutes. By the middle of the 1970s, a number of additional variable white dwarfs had been found, but, like HL Tau 76, they were all white dwarfs of spectral type DA, with hydrogen-dominated atmospheres. In 1982, calculations by Don Winget and his coworkers suggested that helium-atmosphere DB white dwarfs with surface temperatures around 19,000 K should also pulsate., p. L67. Winget then searched for such stars and found that GD 358 was a variable DB, or "DBV", white dwarf. This was the first prediction of a class of variable stars before their observation., p. 89. In 1985, this star was given the variable-star designation "V777 Herculis", which is also another name for this class of variable stars.; , p. 3525


Psi Ursae Majoris

Psi Ursae Majoris (Psi UMa, ψ Ursae Majoris, ψ UMa) is a star in the northern circumpolar constellation of Ursa Major. It has an apparent visual magnitude of +3.01, making it a third magnitude star and one of the brighter members of the constellation. Parallax measurements place it at a distance of from Earth. This is sufficiently close that the magnitude of the star is only reduced by 0.05 due to extinction. In Chinese astronomy, Psi Ursae Majoris is called Tien Tsan or Ta Tsun, "Extremely Honorable". The name was possibly derived from the word 太尊, Pinyin: Tàizūn, meaning "Royals", because this star stands alone as the only member of the "Royals" asterism within the Purple Forbidden enclosure (see Chinese constellation).
The spectrum of this star matches a stellar classification of K1 III, with the luminosity class of 'III' indicating this is an evolved giant star that has exhausted the supply of hydrogen at its core. As a consequence, it has expanded to around 20 times the radius of the Sun. It is radiating roughly 148 times the luminosity of the Sun from its enlarged outer envelope at an effective temperature of 4,520 K. At this heat, the star glows with the orange hue of a K-type star.
Psi Ursae Majoris is a member of the thin disk population of the Milky Way. It is following an orbit through the galaxy with a low eccentricity of 0.02 that will carry it between from the Galactic Center. The low inclination of its orbit means the star will only stray from the galactic plane.


39 Aurigae

39 Aurigae is a single star in the constellation of Auriga. The designation is from the star catalogue of English astronomer John Flamsteed, first published in 1712. The star is just barely visible to the naked eye, having an apparent visual magnitude of 5.90. Based upon an annual parallax shift of 20.11 mas as seen from Earth, it is located 112 light years away. 5 Andromedae is moving further from the Sun with a radial velocity of +34 km/s. It has a relatively high proper motion, advancing across the celestial sphere at the rate of 0.151 arc seconds per year.
This is an F-type main-sequence star with a stellar classification of F1 V. It is an estimated 603 million years old with a relatively high rate of spin, showing a projected rotational velocity of around 88 km/s. The star has 1.45 times the mass of the Sun and it is radiating 9.36 times the Sun's luminosity from its photosphere at an effective temperature of around 7,161 K.