Beta Canis Minoris

Beta Canis Minoris (β Canis Minoris, abbreviated Beta CMi, β CMi), also named Gomeisa , is a star in the constellation of Canis Minor. In the night sky it is notable for its proximity to the prominent star Procyon.
Nomenclature.
"β Canis Minoris" (Latinised to "Beta Canis Minoris") is the star's Bayer designation.
The traditional name "Gomeisa" comes from the Arabic "al-ghumaisa'" ("the bleary-eyed (woman)"), short for مرزم الغميصاء "mirzam al-ghumaisa'" ("girdle of the bleary-eyed one"). In Arabic, the short form would be identical with the name of Procyon. 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 "Gomeisa" for this star.
In Chinese, (), meaning "South River", refers to an asterism consisting of β Canis Minoris, Procyon and Epsilon Canis Minoris. Consequently, β Canis Minoris itself is known as (, .)
Properties.
From parallax measurements, the distance to this star is about . It has an apparent visual magnitude of 2.89, making it easily visible to the naked eye. Beta Canis Minoris has about 3.5 times the Sun's mass and is rotating rapidly with a projected rotational velocity of , which gives a lower bound on the azimuthal rotational velocity along the star's equator. The actual rotation rate may be about once per day.
The stellar classification of this star is B8 Ve. A luminosity class V star belongs on the main sequence, which means it is generating energy through the thermonuclear fusion of hydrogen at its core. The star is radiating this energy from its outer envelope at an effective temperature of 12,050 K, giving it a blue-white hue typical of B-type stars. An 'e' classification indicates that the spectrum contains emission lines, which means this is a Be star that is surrounded by a thin, circumstellar disk made of gaseous material ejected from the star. This hot, gaseous disk is about three times the radius of the star.
Variability.
β Canis Minoris has long been suspected of variability, and in 1977 it was classified as a γ Cassiopeiae variable in the General Catalogue of Variable Stars. A number of studies have found no variation at all. While it shows little variation in brightness, it does display changes in the hydrogen emission coming from the gaseous disk but even those are less pronounced than in many other Be stars.
Examination with the Canadian MOST space telescope reveals changes in the brightness of β Canis Minoris at the milli-magnitude level. This variation has a cyclic pattern formed from multiple overlapping frequencies, with the dominant frequencies being 3.257 and 3.282 cycles per day. As such, it belongs to a class called slowly pulsating B-type (SPB) stars. Be stars that show these types of pulsation have been dubbed SPBe stars.
Possible companion.
It is likely that Beta Canis Minoris is a close binary with a 170-day, eccentric orbit. The companion would have about 42% of the Sun's mass. The nature of the companion is unknown, but it is speculated that it could be a subdwarf O star remaining after binary interactions that spun up the Be primary. If confirmed, this would make it a member of the very rare Phi Persei Be+sdO type systems.


NGC 374

NGC 374 is a spiral or lenticular galaxy located in the constellation Pisces. It was discovered on October 7, 1861 by Heinrich d'Arrest. It was described by Dreyer as "faint, small, between two 15th magnitude stars."


Ashvini

Ashvini (अश्विनी "aśvinī") is the first nakshatra (lunar mansion) in Hindu astronomy having a spread from 0°-0'-0" to 13°-20', corresponding to the head of Aries, including the stars β and γ Arietis. The name "aśvinī" is used by Varahamihira (6th century). The older name of the asterism, found in the Atharvaveda (AVS 19.7; in the dual) and in Panini (4.3.36), was "aśvayúj", "harnessing horses".
Astrology.
Ashvini is ruled by Ketu, the descending lunar node. In electional astrology, Asvini is classified as a small constellation, meaning that it is believed to be advantageous to begin works of a precise or delicate nature while the moon is in Ashvini. Asvini is ruled by the Ashvins, the heavenly twins who served as physicians to the gods. Personified, Asvini is considered to be the wife of the Asvini Kumaras. Ashvini is represented either by the head of a horse, or by honey and the bee hive.
Traditional Hindu given names are determined by which pada (quarter) of a nakshatra the Ascendant/Lagna was in at the time of birth. In the case of Ashvini, the given name would begin with the following syllables: Chu, Che, Cho, La.


49 Aurigae

49 Aurigae is a single star located 680 light years away from the Sun in the northern constellation of Auriga. It is visible to the naked eye as a dim, white-hued star with an apparent visual magnitude of 5.26. The star is moving away from the Earth with a heliocentric radial velocity of +17 km/s, having come to within some 5.5 million years ago. It is positioned near the ecliptic and thus is subject to lunar occultations.
This object is an A-type main-sequence star with a stellar classification of A0 Vnn, where the 'n' notation indicates "nebulous" lines due to rapid rotation. It is spinning with a projected rotational velocity of 149 km/s. This star has around 2.3 times the radius of the Sun and is radiating over three times the Sun's luminosity from its photosphere at an effective temperature of 8,794 K.


Gamma Persei

Gamma Persei (Gamma Per, γ Persei, γ Per) is a binary star system in the constellation Perseus. The combined apparent visual magnitude of the pair is +2.9, making it the fourth-brightest member of the constellation. The distance to this system has been measured using the parallax technique, giving an estimate of roughly with a 4% margin of error. About 4° to the north of Gamma Persei is the radiance point for the annual Perseid meteor shower.
This is a wide eclipsing binary system with an orbital period of 5,329.8 days (14.6 years). This eclipse was first observed in 1990 and lasted for two weeks. During an eclipse, the primary passes in front of the secondary, causing the magnitude of the system to decrease by 0.55. The primary component of this system is a giant star with a stellar classification of G9 III. It has a projected rotational velocity of 50.0 km s−1 and a lengthy estimated rotation period of 14.6 years. The classification of the secondary remains tentative, with assignments of A3 V and A2(III).
Mass estimates for the two stars remain disparate. Using speckle interferometry, McAlister (1982) obtained mass estimates of for the primary and for the secondary, where is the mass of the Sun. He noted that the mass estimate was too high for the given classification of the primary. Martin and Mignard (1998) determined masses for both components based on data from the Hipparcos mission: for the primary and for the secondary. They admit that the high inclination of the orbit resulted in a large margin of error. Prieto and Lambert (1999) came up with a mass estimate of for the primary, while Pizzolato and Maggio (2000) obtained . Ling et al. (2001) obtained estimates of for the primary and for the secondary, while Kaler (2001) obtained 2.5 and 1.9, respectively.


Chi Orionis

Chi Orionis (Chi Ori, χ Orionis, χ Ori) is the name of two stars:
All of them were member of asterism 司怪 (Sī Guài), "Deity in Charge of Monsters", "Turtle Beak" mansion.


NGC 6027b

NGC 6027b is an interacting lenticular galaxy that is part of Seyfert's Sextet, a compact group of galaxies currently in the process of colliding and merging, which is located in the constellation Serpens.


63 Aurigae

63 Aurigae is a single star located around 395 light years away from the Sun in the northern constellation of Auriga. It is visible to the naked eye as a faint, orange-hued star with an apparent magnitude of 4.91. It is moving closer to the Earth with a heliocentric radial velocity of −28 km/s.
This is an evolved giant star with a stellar classification of K4 III. After exhausting the hydrogen at its core, the star has expanded to 37 times the radius of the Sun. It is radiating 335 times the Sun's luminosity from its enlarged photosphere at an effective temperature of 4,068 K.


Gamma Coronae Borealis

Gamma Coronae Borealis, Latinized from γ Coronae Borealis, is a binary star system in the northern constellation of Corona Borealis. It is visible to the naked eye with an apparent visual magnitude of 3.83. Based upon an annual parallax shift of 22.33 mas as seen from Earth, it is located about 146 light years from the Sun. The system is moving closer to the Sun with a radial velocity of about −15 km/s.
Binary system.
The components of this system have been optically separated, with the secondary lying about one arc second away from the primary. They have an orbital period of 91.2 years and an eccentricity of 0.48. The semimajor axis is 0.73 arc seconds − roughly the distance from the Sun to Neptune − and the inclination of the orbital plane is 94.5°. Both components are main sequence stars: the visual magnitude 4.04 primary has a stellar classification of B9 V, while the secondary is of class A3 V and magnitude 5.60.
Variability.
In 1969, γ Coronae Borealis was confirmed to be variable with an amplitude of 0.05 magnitudes. A year later, it was "confirmed" to be a δ Scuti variable with the earliest known spectral type in the class. The observed variations were not strictly periodic, but showed a characteristic timescale of 0.03 days (43 minutes). γ Coronae Borealis also showed anomalous behaviour not seen in other δ Scuti stars, such as periods without variation.
When the pulsation mechanisms of the δ Scuti stars and the similar but hotter Slowly pulsating B-type (SPB) stars were identified, it became apparent that γ Coronae Borealis and a handful of similar low amplitude variable stars such as γ Ursae Minoris and Maia fell between those two classes in a region with no known driver for pulsations. The "Maia variable" class was named for these stars. Ironically, Maia itself has been shown not to be variable, and a number of other reported members of the class have been shown to be variables of other types, so the Maia variables appear to be very rare if they are even a real variable class. However, satellite observations have discovered a number of small-amplitude variables between the SPB and δ Scuti instability regions as well as a number of candidates in the open clusters NGC 3766 and NGC 1893.
The mechanism of variability for γ Coronae Borealis is not known. Spectroscopic variations with a period of 0.9 days have been observed, which matches the likely rotation period of the star, and radial velocity changes are also seen with a possible period of 0.45 days. Short-period non-radial pulsations may be carried around by the rotation of the star, but the driver of such pulsations in a star of this temperature is unknown.


NGC 5927

NGC 5927 is a globular cluster in the constellation Lupus. NGC 5927 has a diameter of about 12 arcminutes and an apparent magnitude of +8.86. Its Shapley–Sawyer Concentration Class is VIII, and it contains stars of magnitude 15 and dimmer.
The globular cluster was discovered by the astronomer James Dunlop in 1826 and was also observed in 1834 by John Herschel.
NGC 5927 is relatively metal-rich for a globular cluster, and may have multiple generations of stars.


Chi Persei

Chi Persei (Chi Per, χ Persei, χ Per) is the name of a star and an open cluster:


Rho Orionis

Rho Orionis, Latinized from ρ Orionis, is the Bayer designation for an orange-hued binary star system in the equatorial constellation of Orion. It is visible to the naked eye with an apparent visual magnitude of +4.44. The star shows an annual parallax shift of 9.32 mas due to the orbital motion of the Earth, which provides a distance estimate of roughly 350 light years from the Sun. It is moving away from the Sun with a radial velocity of +40.5 km/s. About 2.6 million years ago, Rho Orionis made its perihelion passage at a distance of around .
This is a single-lined spectroscopic binary system with an orbital period of 2.8 years and an eccentricity of 0.1. The visible component is an evolved giant star of type K with a stellar classification of K0 III. Its measured angular diameter is , which, at its estimated distance yields a physical size of about 25 times the radius of the Sun. It has 2.67 times the mass of the Sun and is about 650 million years old. The star is radiating 251 times the Sun's luminosity from its enlarged photosphere at an effective temperature of 4,533 K.


Lilium (constellation)


Xi2 Lupi

Xi2 Lupi (ξ2 Lup, ξ2 Lupi) is a member of a double star with Xi1 Lupi in the southern constellation of Lupus. As of 2004, the pair had an angular separation of 10.254 arc seconds along a position angle of 49.21°. Xi2 Lupi is visible to the naked eye with an apparent visual magnitude of 5.55. Based upon an annual parallax shift of 21.71 mas as seen from Earth, it is located roughly 150 light years from the Sun. It has a peculiar velocity of relative to its neighbors, and is probably (86% chance) a runaway star.
This is a B-type main sequence star with a stellar classification of B9 V. It has an estimated 2.38 times the mass of the Sun and radiates 10.6 times the Sun's luminosity from its outer atmosphere at an effective temperature of 9,725 K. Xi2 Lupi is about 381 million years old and is spinning relatively rapidly with a projected rotational velocity of 184 km/s.


Upsilon Aurigae

Upsilon Aurigae, Latinized from υ Aurigae, is the Bayer designation for a star in the northern constellation of Auriga. It has an apparent visual magnitude of 4.74, which means it is bright enough to be seen with the naked eye. Based upon parallax measurements made during the Hipparcos mission, this star is approximately distant from the Earth.
This is an evolved red giant star with a stellar classification of M0 III. It is a suspected variable star and is currently on the asymptotic giant branch, which means it is generating energy at its core through the fusion of helium. The measured angular diameter of this star, after correction for limb darkening, is . At the estimated distance of Upsilon Aurigae, this yields a physical size of about 73 times the radius of the Sun.
References.
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74 Ophiuchi

74 Ophiuchi is a suspected binary star in the equatorial constellation of Ophiuchus, near the border with Serpens Cauda. It is visible to the naked eye as a faint, yellow-hued point of light with a combined apparent visual magnitude of 4.85. The system is located at a distance of 238 light years from the Sun based on parallax, and is drifting further away with a radial velocity of +4.4 km/s.
The primary member, designated component A, is an aging giant star with a stellar classification of G8III and an estimated age of 1.73 billion years. Having exhausted the hydrogen supply at its core, the star has expanded to 10.5 times the Sun's radius. It is a red clump giant, which means it is on the horizontal branch and is generating energy through helium fusion at its core. The star has 2.4 times the mass of the Sun and is radiating 66 times the Sun's luminosity from its swollen photosphere at an effective temperature of around 5,073 K.
The magnitude 11.5 secondary, component B, lies at an angular separation of from the primary, as of 2008. A visual companion, component C, is magnitude 12.28 and has a separation of .


List of stars in Corvus

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


Westerhout 43

Westerhout 43, also known as W43, is a region of star formation of our galaxy located in the constellation of Aquila at a distance of 6 kilo-parsecs (nearly 20,000 light-years) of the Sun, that is considered the region of the Milky Way that is most actively forming stars. Despite this, however, it is so heavily obscured by the interstellar dust that it is totally invisible in the optical and must be studied using other wavelengths that are not affected by it, such as the infrared or the radio waves.
Physical properties.
This star-forming region is located in the "5-kpc ring", a ring with that radius that encircles the central bar of our galaxy and that contains most of its molecular hydrogen as well as most of its star formation.
It is associated with a very massive complex of molecular clouds with a total mass of more than 7 million times the one of our Sun and is forming stars of all masses within star clusters that are less massive versions of those found on starburst galaxies; it still has capacity to form more clusters.
There are also massive protostars as well as stellar clusters in formation embedded within the nebula, with this star formation region likened to NGC 3603
W43's center, finally, contains a dense and massive star cluster with several O stars and Wolf-Rayet stars that has been compared due to its compactness to NGC 3603 or even Large Magellanic Cloud's R136.


Kappa Telescopii

Kappa Telescopii (κ Telescopii) is a solitary, yellow-hued star in the southern constellation of Telescopium. With an apparent visual magnitude of +5.20, it is visible to the naked eye. Based upon an annual parallax shift of 12.00 mas as seen from Earth, it is located around 272 light years from the Sun.
At the age of around 1.25 billion years, this an evolved giant star with a stellar classification of G8/K0 III, showing a spectrum with characteristics intermediate between a G-type and a K-type star. It has an estimated 1.9 times the mass of the Sun and 10.5 times the Sun's radius. The star is radiating 77.6 times the solar luminosity from its photosphere at an effective temperature of 4,968 K. It is unclear whether it is cooling or heating up on its evolutionary pathway through the red clump.


NGC 2227

NGC 2227 is a barred spiral galaxy with a morphological type of SB(rs)c located in the direction of the Canis Major constellation. It was discovered on January 27, 1835, by John Herschel.
In 1986, a type Ia supernova with an apparent magnitude of 14.0 was detected within NGC 2227, and was designated SN 1986O.


38 Leonis Minoris

38 Leonis Minoris is a binary star system in the northern constellation of Leo Minor. It shines with a combined light of apparent magnitude 5.84, which indicates it a dimly visible to the naked eye under good viewing conditions. An annual parallax shift of 19.11 mas provides a distance estimate of around 171 light years. It has a relatively high proper motion, traversing the celestial sphere at a rate of 0.226 arcseconds per year, and is moving away from the Sun with a radial velocity of +31 km/s.
This is a single-lined spectroscopic binary with an orbital period of 7.8 days and a low eccentricity of 0.023 – nearly circular. The visible component has a stellar classification of G0 IV, matching a G-type subgiant star that is exhausting the hydrogen at its core and evolving into a giant. It is about two billion years old with 1.68 times the mass of the Sun and is spinning with a projected rotational velocity of 14.5 km/s. The star has a higher than solar abundance of iron in its spectrum. It is radiating 11 times the Sun's luminosity from its photosphere at an effective temperature of 6,106 K.


Omega Eridani

Omega Eridani (ω Eri) is a binary star system in the constellation Eridanus. It is visible to the naked eye with an apparent visual magnitude is 4.37. The distance to this star, as determined by the parallax method, is around 235 light years.
This is a single-lined spectroscopic binary system with an orbital period of 3,057 days (8.4 years) and an eccentricity of 0.46. The primary component is an A-type subgiant star with a stellar classification of A9 IVn, where the 'n' suffix indicates a broad ("nebulous") absorption due to rotation. The projected rotational velocity is 186 km/s. This is giving the star an oblate shape with an equator that is 13% wider than the polar radius. The angular size of Omega Eridani is 0.87 mas. At an estimated distance of the star, this yields a physical size of around 6.7 times the radius of the Sun.
References.
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HD 82785

HD 82785 is star in the southern constellation of Antlia.


Iota Cancri

Iota Cancri (ι Cnc, ι Cancri) is a double star in the constellation Cancer approximately 300 light years from Earth. It also has the name "Decapoda".
The two stars of ι Cancri are separated by 30 arcseconds, changing only slowly. Although no orbit has been derived, the two stars show a large common proper motion and are assumed to be gravitationally related.
The brighter star, ι Cancri A, is a yellow G-type giant with an apparent magnitude of +4.02. It is a mild barium star, thought to be formed by mass transfer of enriched material from an asymptotic giant branch star onto a less evolved companion. No such donor has been detected in the ι Cancri system, but it is assumed that there is an unseen white dwarf.
The fainter of the two stars, ι Cancri B, is a white A-type main sequence dwarf with an apparent magnitude of +6.57. It is a shell star, surrounded by material expelled by its rapid rotation.


HD 40873

HD 40873 is a star in the northern constellation of Auriga, a few degrees to the south of Delta Aurigae. Located around 455 light-years distant, it shines with a luminosity approximately 38 times that of the Sun and has an effective temperature of 7,753 K. It is a suspected variable star and has a fairly rapid rotation rate, showing a projected rotational velocity of 134 km/s. Eggen (1985) suggested it is a probable member of the Hyades Supercluster.
Samuel Molyneux named this star Telescopica in Auriga. Flamsteed catalogued it as 35 Camelopardali Heveliana, which is the name James Bradley continued to use, although it is within the borders of the modern constellation Auriga. Francis Baily reclassified it to Auriga as star 1924 in the British Association's 1845 Catalogue of 8377 Stars.
HD 40873 is considered to be an Am star, a chemically peculiar star with unusually strong absorption lines of metals. It has been given a spectral type of kA5mA7IV, although other catalogues have given more normal classifications such as A7 V or A7 III.
Components.
HD 40873 has a 9th magnitude class A5 companion about half an arc-minute away. It is designated as SAO 25549. The companion is itself a pair of stars, each of similar brightness, separated by 0.6".


Phi Capricorni

Phi Capricorni (φ Cap, φ Capricorni) is a solitary star in the southern constellation of Capricornus. It is visible to the naked eye with an apparent visual magnitude of +5.16. Based upon an annual parallax shift of 5.07 mas as seen from the Earth, the star is located about 640 light years from the Sun, give or take 30 light years.
This is an evolved, orange-hued K-type giant/bright giant star with a stellar classification of K0 II-III It shows an infrared excess, which may be due to leftover material from a mass-loss event. The star has an estimated 2.63 times the mass of the Sun, and radiates 447 times the solar luminosity from its photosphere at an effective temperature of 4,490 K. Phi Capricorni is around 1.24 billion years old and is spinning with a projected rotational velocity of 3.8 km/s.
Chinese Name.
In Chinese, (), meaning "Twelve States", refers to an asterism which is represent twelve ancient states in the Spring and Autumn period and the Warring States period, consisting of φ Capricorni, ι Capricorni, 38 Capricorni, 35 Capricorni, 36 Capricorni, χ Capricorni, θ Capricorni, 30 Capricorni, 33 Capricorni, ζ Capricorni, 19 Capricorni, 26 Capricorni, 27 Capricorni, 20 Capricorni, η Capricorni and 21 Capricorni. Consequently, the Chinese name for φ Capricorni itself represents the state Chu (), together with ε Ophiuchi in "Right Wall of Heavenly Market Enclosure" (asterism).
R. H. Allen had opinion that φ Capricorni, together with χ Capricorni, were represent the state Wei (魏).


NGC 527

NGC 527, also occasionally referred to as PGC 5128 or PGC 5141, is a lenticular galaxy located approximately 259 million light-years from the Solar System in the constellation Sculptor. It was discovered on 1 September 1834 by astronomer John Herschel.
Observation history.
Herschel discovered the object along with NGC 526. The object was later catalogued by John Louis Emil Dreyer in the New General Catalogue, where the galaxy was described as "faint, small, a little extended, brighter middle, the following (eastern) of 2" with the other one being NGC 526.
Description.
The galaxy has an apparent visual magnitude of 13.2 and can be classified as type SB0-a using the Hubble Sequence. The object's distance of roughly 260 million light-years from the Solar System can be estimated using its redshift and Hubble's law.
Companion Galaxy PGC 5142.
NGC 527 has a much dimmer magnitude 14 companion galaxy (PGC 5142). Although this galaxy is not an NGC object, it is sometimes referred to as NGC 527B. The galaxy has an apparent size of 1.6' × 0.3' and a recessional velocity of approximately 5880 km/s.


NGC 546

NGC 546 (also known as ESO 296-25, IRAS 01229-3819, MCG −6-4-29 and PGC 5255) is a barred spiral galaxy about 270 million light years away from Earth and located in the constellation Sculptor. The largest diameter is 1.40 (122 thousand light years) and the smallest is 0.5 angular minutes (43 thousand light years). The first discovery was made by John Frederick William Herschel on 23 October 1835.


Y Carinae

Y Carinae (Y Car) is a Classical Cepheid variable, a type of variable star, in the constellation Carina. Its apparent magnitude varies from 7.53 to 8.48.
The primary Cepheid pulsation period is 3.6 days, but it also pulsates with a secondary period of 2.56 days. It is known as a double-mode Cepheid, or a beat Cepheid since the two periods interfere to produce slow variations at a beat frequency.
The variable primary star is in a triple system with a very close pair of hot main sequence stars. The period of the outer pair is 2.76 years. The inner pair are constrained to orbit in less than 31 days, but the exact nature of the orbit is unknown. The existence of the close binary pair throws into doubt previous calculations of the mass of the pulsating star. The existence of high numbers of triple systems and short period Cepheids suggests that some at least of the short period Cepheids may have formed by mergers.


R Pictoris

R Pictoris is a semiregular variable type star in the constellation Pictor. It ranges between apparent magnitude 5.1 and 14.4, and spectral types M1IIe to M4IIe, over a period of 168 days.


68 Ophiuchi

68 Ophiuchi is a binary star system in the equatorial constellation of Ophiuchus. It is visible to the naked eye as a faint star with an apparent visual magnitude of 4.42. The system is located around distant from the Sun, based on parallax, and is drifting further away with a radial velocity of +6 km/s.
This is a spectroscopic binary with an orbital period of 177 years and an eccentricity of 0.83. The brighter member, component A, is an A-type main-sequence star of spectral type A2Vn, a star that is currently fusing its core hydrogen. The 'n' suffix indicates "nebulous" lines due to rapid rotation. The star is suspected of varying between magnitudes 4.42 and 4.48. It displays an infrared excess that matches a circumstellar disk of dust orbiting from the star with a mean temperature of 160 K. The secondary companion, component B, is of magnitude 7.48.


NGC 380

NGC 380 is an elliptical galaxy located in the constellation Pisces. It was discovered on September 12, 1784 by William Herschel. It was described by Dreyer as "pretty faint, small, round, suddenly brighter middle." Along with galaxies NGC 375, NGC 379, NGC 382, NGC 383, NGC 384, NGC 385, NGC 386, NGC 387 and NGC 388, NGC 380 forms a galaxy cluster called Arp 331.


Omicron Persei

Omicron Persei (ο Persei, abbreviated Omicron Per, ο Per) is a triple star system in the constellation of Perseus. From parallax measurements taken during the Hipparcos mission it is approximately 1,100 light-years (330 parsecs) from the Sun.
The system consists of a spectroscopic binary pair designated Omicron Persei A and a third companion Omicron Persei B. A's two components are themselves designated Omicron Persei Aa (officially named Atik , the traditional name of the system) and Ab.
Nomenclature.
"ο Persei" (Latinised to "Omicron Persei") is the system's Bayer designation. The designations of the two constituents as "Omicron Persei A" and "B", and those of "A's" components - "Omicron Persei 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).
It bore the traditional name "Atik" (also "Ati", "Al Atik"), Arabic for "the shoulder". Some sources, including a planetarium software package, an atlas, and a web site attribute the name "Atik" to the nearby, brighter star Zeta Persei. In 2016, the International Astronomical Union organized a Working Group on Star Names (WGSN) to catalogue and standardize proper names for stars. The WGSN decided to attribute proper names to individual stars rather than entire multiple systems. It approved the name "Atik" for the component Omicron Persei A on 12 September 2016 and it is now so included in the List of IAU-approved Star Names.
In Chinese, (), meaning "Rolled Tongue", refers to an asterism consisting of Omicron Persei, Nu Persei, Epsilon Persei, Xi Persei, Zeta Persei and 40 Persei. Consequently, the Chinese name for Omicron Persei itself is (), "the Fifth Star of Rolled Tongue".
Namesake.
USS "Atik" was a ship of the United States Navy.
Properties.
Omicron Persei A is a spectroscopic binary consisting of a spectral type B1 giant and a type B2 dwarf orbiting each other every 4.4 days. The orbit is near-circular although its inclination is not precisely known. The two stars are separated by approximately , the exact value depending on the inclination. The primary is approximately one magnitude brighter than the secondary at visual wavelengths.
Omicron Persei lies just north of the open cluster IC 348, but is not catalogued as a member. Both IC 348 and Omicron Persei belong to the Perseus OB2 association.


Arp 240

Arp 240 is a pair of interacting spiral galaxys located in the constellation Virgo. The two galaxies are listed together as Arp 240 in the Atlas of Peculiar Galaxies. The galaxy on the right is known as NGC 5257, while the galaxy on the left is known as NGC 5258. Both galaxies are distorted by the gravitational interaction, and both are connected by a tidal bridge, as can be seen in images of these galaxies.


S Persei

S Persei is a red supergiant or hypergiant located near the Double Cluster in Perseus, north of the cluster NGC 869. It is a member of the Perseus OB1 association and one of the largest known stars. If placed in our solar system, its photospehere would engulf the orbit of Jupiter. It is also a semiregular variable, a star whose variations are less regular than those of Mira variables.
Discovery.
S Persei was named by German astronomer Adalbert Krueger in 1874 after observing that it varied in brightness. It was subsequently listed in major stellar catalogues of that era as HD 14528 and BD+57°552.
Variability.
S Persei varies slowly by several magnitudes, a factor of over 40 in brightness. It has a main period of somewhat over two years, but shows significant unpredictability. There is a strong variation in the amplitude from around one magnitude to about four magnitudes, and these have been interpreted as beats due to a second period of about 940 days. Other analyses find only the primary period of 813 ± 60 days.
S Persei is classified as a semiregular variable star of type SRc, indicating that it is a supergiant, and it has one of the largest visual amplitudes of any variable of this type. While the General Catalogue of Variable Stars lists it as varying between magnitudes 7.9 and 12.0, it has since been seen fainter.
The spectral type of S Persei also varies. Typically it is a red supergiant of spectral class M3 or M4, but particularly at deep visual minima it may show a much cooler spectral type of M7 or M8, highly unusual for a supergiant.
Properties.
Many of the visually bright variable stars belong to this class of semiregulars, as these stars are extremely large and luminous, and hence visible across long distances. S Persei has been described as a hypergiant and has a radius over 700 times the sun's radius (). Its angular diameter has been measured directly and found to be somewhat elliptical. Modelled as a uniform disk, the radius corresponds to .
The temperature has been calculated from the spectrum using a DUSTY model, giving an effective photospheric temperature of 3,500 K and a temperature of 1,000 K for the surrounding dust torus. This is consistent with previous studies, but the derived luminosity from different authors varies from to . Older studies frequently calculated higher luminosities, lower temperatures, and consequently larger values for the radius.
The mass of S Persei is also uncertain, but expected to be around . Mass is being lost at 2.4 to per year, leading to an extensive and complex circumstellar environment of gas and dust.
Location.
S Persei is surrounded by clouds containing water molecules which produce maser emission. This allows the distance to be measured very accurately using very long baseline interferometry, giving an annual parallax of 0.413 ± 0.017 milliarcseconds. For comparison the Gaia Data Release 2 parallax is . It lies somewhat further away than the centres of the Double Cluster open clusters, but definitely within the Per OB1 association and the Perseus Arm of the galaxy.
S Persei is a double star. The red supergiant has an A0 11th magnitude companion at 69". There are also several other 8th to 10th magnitude stars within half a degree of S Persei.


22 Orionis

22 Orionis is a binary star in the equatorial constellation of Orion. It has the Bayer designation o Orionis, while "22 Orionis" is the Flamsteed designation. This system is visible to the naked eye as a faint, blue-white hued star with an apparent visual magnitude of 4.74. It is located approximately 1,100 light years away from the Sun based on parallax. The system is moving further from the Earth with a heliocentric radial velocity of +28.80
This is a single-lined spectroscopic binary with an orbital period of 293 days and an eccentricity of 0.15. The visible member, component A, has a stellar classification of B2 IV-V, matching a B-type star with a luminosity class that displays mixed traits of a main sequence star and a subgiant. It is a suspected Beta Cephei variable or a slowly pulsating B star. The star has nine times the mass of the Sun and is radiating 741 times the Sun's luminosity from its photosphere at an effective temperature of .


John Bevis

John Bevis (10 November 1695 in Salisbury, Wiltshire – 6 November 1771) was an English doctor, electrical researcher and astronomer. He is best known for discovering the Crab Nebula in 1731.
Bevis has also observed an occultation by Venus of Mercury on 28 May 1737 NS, (17 May 1737 OS) and observed and found a prediction rule for eclipses of Jupiter's moons. From observations made with his telescope at Stoke Newington, Middlesex, he compiled a star catalogue (more of an atlas) entitled "Uranographia Britannica" around 1750.
In 1757 Bevis published in London a volume on "The History and Philosophy of Earthquakes" in which he collected accounts of the Lisbon earthquake from diverse authentic sources. His survey, the first of its kind, was subsequently used by John Michell (1761).
In 1757 Bevis was asked by the tobacconist Thomas Hughes to discover why no flowers would grow in his garden at Bagnigge House, which stood in the vicinity of 61-63 King's Cross Road, London. He found the water from the well on the site to be full of iron. On this research, a second well was dug, the water from which was found to be a good purgative. This led to the establishment of one of the most popular 18th Century spas, Bagnigge Wells, the following year.
He was elected a Fellow of the Royal Society in November, 1765. He received his B.A. from Christ Church, Oxford in 1715 and M.A. there also in 1718.
Electrical research.
When the Leyden Jar first arrived in the UK (1746), Bevis worked with William Watson in refining it. They removed the water and replaced it with lead shot, then later lined the inside and exterior of the glass with lead. They also experimented to determine the speed of electricity using nearly four kilometers of wire and observing the spark made on entering the wire, and that made on leaving it: they could not detect any time delay and concluded it must be almost instantaneous.
Watson and Bevis corresponded extensively with Benjamin Franklin and his group of Philadelphia experimenters and they jointly:


Mu Tauri

μ Tauri, Latinized as Mu Tauri, is a single star in the equatorial constellation of Taurus. It has a blue-white hue and is faintly visible to the naked eye with an apparent visual magnitude of 4.27. The star is located approximately 490 light years distant from the Sun based on parallax, and is drifting further away with a radial velocity of +16 km/s.
This object has a stellar classification of B3IV, matching a B-type subgiant star. In the past this star was thought to have a variable radial velocity, but is now considered constant. It is 252 million years old and is spinning with a projected rotational velocity of 89 km/s. The star has 6.7 times the mass of the Sun and is radiating 462 times the Sun's luminosity from its photosphere at an effective temperature of 16,980 K. It is emitting an infrared excess at a wavelength of , making it a candidate host of a faint warm debris disk.


NGC 657

NGC 657 is an open cluster containing very few stars or a group of stars located in the constellation Cassiopeia. It was discovered by British astronomer John Herschel in 1831.


Red Square Nebula

The Red Square Nebula is a celestial object located in the area of the sky occupied by star MWC 922 in the constellation Serpens. The first images of this bipolar nebula, taken using the Mt. Palomar Hale telescope in California, were released in April 2007. It is notable for its square shape, which according to Sydney University astrophysicist Peter Tuthill, makes it one of the most nearly discrete-symmetrical celestial objects ever imaged.
The explanation proposed by Tuthill and his collaborator James Lloyd of Cornell University is that the square shape arises from two cone shapes placed tip-to-tip, as seen from the side. This also explains the "double-ring" structure seen in SN 1987A.
A series of faint spokes radiate from the center of the structure. One possible explanation is that these spokes are shadows cast by periodic ripples or waves on the surface of an inner disk close to the central star.
There is no clear explanation of how the central star could produce the nebula's shape:
Towards the end of their lives, many low-mass stars, like the Sun, slough off their outer layers to produce striking 'planetary' nebulae. But the hot star at the heart of the Red Square nebula, called MWC 922, appears to be relatively massive, suggesting another process formed its signature shape. "How did all this beautiful, crisp structure form?" asks Peter Tuthill of the University of Sydney in Australia. "This is the million dollar question."


HR 5553

HR 5553 is a binary star system located thirty-eight light-years away from the Sun, in the northern constellation Boötes. It has the variable star designation DE Boötis, and is classified as an RS Canum Venaticorum variable that ranges in apparent visual magnitude from 5.97 down to 6.04, which is bright enough to be dimly visible to the naked eye. The system is drifting closer to the Sun with a radial velocity of −30 km/s, and is expected to come as close as in 210,000 years.
Orbital elements for this single-lined spectroscopic binary was first calculated in 1981 using radial velocity measurements from David Dunlap Observatory combined with older measurements from Mount Wilson Observatory and Dominion Astrophysical Observatory. The two stars orbit each other with a period of 125 days and a large eccentricity of 0.51.
The primary, designated component A, is a K-type main sequence star with a stellar classification of K0 V. It is around one billion years old and is spinning with a projected rotational velocity of 4 km/s.The star has 84% of the mass of the Sun and 86% of the Sun's radius. It is radiating 50% of the luminosity of the Sun from its photosphere at an effective temperature of 5,313 K. Component B has an estimated 45% of the mass of the Sun.
An infrared excess has been detected around this system, most likely indicating the presence of a circumstellar disk at a radius of 34.2 AU. The temperature of this dust is 40 K. The estimated mass of the dust is 0.0002 times the mass of the Earth. It is aligned to within 10° of the plane of the binary system.


Sh2-7

Sh2-7 is an emission nebula in the Scorpius constellation. The nebula is around the star Delta Scorpii. It lies next to a large reflection nebula, Sh2-1.
According to the paper "Interstellar magnetic cannon targeting the Galactic halo. A young bubble at the origin of the Ophiuchus and Lupus molecular complexes", the HII region Sh2-7 may be acting as a faraday screen, altering the polarization of the GCS.


99 Herculis

99 Herculis is the Flamsteed designation for a binary star system in the northern constellation of Hercules. It has the Bayer designation b Herculis, while "99 Herculis" is the Flamsteed designation. This system has an apparent visual magnitude of 5.1, which, according to the Bortle scale, makes it faintly visible to the naked eye from suburban skies. Measurements made with the Hipparcos spacecraft show an annual parallax shift of 0.064″, corresponding to a physical distance of about from the Sun. The system is moving further from the Earth with a heliocentric radial velocity of +1.7 km/s.
The binary nature of this star system was first discovered in 1859 by English astronomer W. R. Dawes. The two stellar components orbit around their common center of mass, or barycenter, with a period of 56.3 years and an eccentricity of 0.766. The semi-major axis of their orbit spans an angle of 1.06 arcseconds, which corresponds to a physical dimension of 16.5 AU. The plane of their orbit is inclined by an angle of about 39° to the line-of-sight from the Earth. Reports of a third component of this system now appear doubtful.
The primary component, 99 Herculis A, is an F-type main sequence star with a stellar classification of F7 V. It has 94% of the Sun's mass and nearly double the luminosity, but has an estimated 10% greater radius. The effective temperature of the star's outer atmosphere is 5,938 K, giving it a white-hued glow. This is a metal-poor star, showing overall abundances of elements—other than hydrogen or helium—equal to 60% of those in the Sun.
The secondary component, 99 Herculis B, is fainter by 3.35 magnitudes compared to the primary. It is a K-type main sequence star with a classification of K4 V. With 46% of the mass of the Sun, it has 74% of the Sun's radius but shines with just 14% of the Sun's luminosity.
Images from the Herschel Space Observatory show that a disk of dusty debris is orbiting the barycenter at an average radius of 120 AU. Oddly, the disk appears to be misaligned with the orbital plane of the binary system. This may be the result of an interaction within another star system some time in the past. Most of the disk emission appears to be caused by icy objects having a diameter of 10 cm or less, with a net mass of about ten times the mass of the Earth.


Lambda Tauri

Lambda Tauri (λ Tau, λ Tauri) is a triple star system in the constellation Taurus. In the "Calendarium of Al Achsasi Al Mouakket", this star was designated "Sadr al Tauri", which was translated into Latin as "Pectus Tauri", meaning "the bull chest". In 1848, the light from this system was found to vary periodically and it was determined to be an eclipsing binary system—the third such discovered. The components of this system have a combined apparent visual magnitude of +3.47, making it one of the brighter members of the constellation. Based upon parallax measurements from the Hipparcos mission, the distance to this system is approximately .
System.
The inner pair of this triple star system, Lambda Tauri AB, orbit around each other with a period of 3.95 days and a low eccentricity of about 0.025. Their orbital plane is inclined by around 76° to the line of sight from the Earth, so it is being viewed from nearly edge on and the two stars form an Algol-like eclipsing binary system. The combined brightness of the pair varies from magnitude +3.37 to +3.91 as first one star and then the other pass in front of its companion. The primary member, λ Tau A, undergoes a decrease of 0.435 ± 0.050 in magnitude during an eclipse, while the secondary component, λ Tau B, decreases by 0.09–0.10 in magnitude. The mean physical separation between these two stars is estimated at 21.91 times the radius of the Sun, or 0.1 Astronomical Units.
The primary component has a stellar classification of B3 V, making this a massive B-type main sequence star. It has over seven times the mass of the Sun and 6.4 times the Sun's radius. This star is the brightest member of the system, radiating about 5,801 times the luminosity of the Sun from its outer envelope at an effective temperature of 18,700 K, which gives it a blue-white hue common to the B-type stars. Lambda Tauri A is rotating rapidly with a projected rotational velocity of . It, along with δ Librae, were the first stars on which rotational line broadening was observed, by Frank Schlesinger in 1909.
The third component, λ Tau C, is orbiting the inner pair over a 33.025 day period with an eccentricity of roughly 0.15. The orbital plane of this component is nearly coplanar with the orbit of Lambda Tauri AB, differing by no more than 7°. It has about half the mass of the Sun. The orbit of this star causes perturbation effects on the orbit of the AB pair, resulting in periodic changes in their orbital eccentricity and other orbital elements.
Physical characteristics.
The spectrum of Lambda Tauri A shows an under abundance of carbon relative to the norm for this category of star. A possible explanation for this is a loss of mass by the star some time in the past. An inner region of the star became depleted by the conversion of carbon into nitrogen during the nuclear fusion process, and this region was later exposed when the outer envelope of the star was lost. Alternatively, the star may have undergone a period of convective mixing, bringing the carbon-depleted material to the surface. However, the cause of such a fully convective behavior in a main sequence star of this mass is unclear.
The secondary companion has a stellar classification of A4 IV, suggesting that it is a subgiant star that has nearly exhausted the supply of hydrogen at its core and is in the process of evolving into a giant star. It has nearly 1.9 times the mass of the Sun, 5.3 times the Sun's radius, and is radiating 128 times the Sun's luminosity at an effective temperature of 8,405 K. As with the primary, this star is spinning rapidly with a projected rotational velocity of . The side of the secondary facing the more massive star is being heated by an additional 1,440 K, which produces a rotational effect that causes the strength of the secondary's spectral lines to vary over the course of its orbit.
A conundrum with this system is the large radius of the secondary star. In stellar evolutionary terms, the more massive primary should be the first to reach the subgiant stage. Hence the enlarged radius of the secondary must be caused by a means other than the star's age. This suggests that the pair Lambda Tauri AB form a semidetached binary with the secondary filling its Roche lobe, giving it a distorted shape.


NGC 2659

NGC 2659 is an open cluster in the constellation Vela. It was discovered by John Herschel on 3 February, 1835. It is of Trumpler class III3m. It is a young cluster, with age nearly 8 million years. The core of the cluster is 1.93 parsec (6.3 light years) across and the total radius is 3.6 pc (11.7 light years). The total numbers of star that belong to the cluster is estimated to be 1,801 ± 608 stars and the total mass 857 ± 237 . Among its members, one is a Be star, with four more possible Be stars.


Pi Pegasi

The Bayer designation Pi Pegasi (π Peg / π Pegasi) is shared by two stars, in the constellation Pegasus:
They are separated on the sky by , or one-sixth of a degree.


F Puppis

The Bayer designations f Puppis and F Puppis are distinct and refer to two different stars in the constellation Puppus:


NGC 7789

NGC 7789 (also known as Caroline's Rose or the White Rose Cluster) is an open cluster in Cassiopeia that was discovered by Caroline Herschel in 1783. Her brother William Herschel included it in his catalog as H VI.30. This cluster is also known as the "White Rose" Cluster or "Caroline's Rose" Cluster because when seen visually, the loops of stars and dark lanes look like the swirling pattern of rose petals as seen from above.


HR 3830

HR 3830 is an orange giant star, type K0III, in the southern hemisphere constellation of Antlia. It is 311 light years from Earth. Its apparent magnitude is 5.68.


Cor Caroli

The Cor Caroli system is a binary star designated Alpha Canum Venaticorum (α Canum Venaticorum, abbreviated Alpha CVn, α CVn). The International Astronomical Union uses the name "Cor Caroli" specifically for the brighter star of the binary. Alpha Canum Venaticorum is the brightest point of light in the northern constellation of Canes Venatici.
Nomenclature.
"α Canum Venaticorum" (Latinised to "Alpha Canum Venaticorum") is the system's Bayer designation. The brighter of the two stars is designated "α2 Canum Venaticorum", the fainter "α1 Canum Venaticorum".
In the western world Alpha Canum Venaticorum had no name until the 17th century, when it was named "Cor Caroli", which means "Charles's Heart". There has been some uncertainty whether it was named in honour of King Charles I of England, who was executed in 1649 during the English Civil War, or of his son, Charles II, who restored the English monarchy to the throne in 1660. The name was coined in 1660 by Sir Charles Scarborough, physician to Charles II, who claimed the star seemed to shine exceptionally brightly on the night of Charles II's return to England. In "Star Names", R.H. Allen claimed that Scarborough suggested the name to Edmond Halley and intended it to refer to Charles II. However, Robert Burnham Jr. notes that "the attribution of the name to Halley appears in a report published by J. E. Bode at Berlin in 1801, but seems to have no other verification". In "Star Tales", Ian Ridpath points out that the name's first appearance on a star map was in the 1673 chart of Francis Lamb, who labelled it "Cor Caroli Regis Martyris" ('the heart of Charles the martyred king'), clearly indicating that it was seen as referring to Charles I.
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 "Cor Caroli" for the star α2 Canum Venaticorum.
In Chinese, (), meaning "Imperial Guards", refers to an asterism consisting of α Canum Venaticorum, 10 Canum Venaticorum, Beta Canum Venaticorum, 6 Canum Venaticorum, 2 Canum Venaticorum, 67 Ursae Majoris. Consequently, the Chinese name for Alpha Canum Venaticorum itself is (, .) From this Chinese name, the name "Chang Chen" was derived.
Stellar properties.
Alpha Canum Venaticorum is a binary star with a combined apparent magnitude of 2.81. The two stars are 19.6 arcseconds apart in the sky and are easily resolved in small telescopes. The system lies approximately 110 light years from the Sun.
It marks the northern vertex of the asterism known as the Great Diamond or the Diamond of Virgo.
α2 Canum Venaticorum.
α2 Canum Venaticorum has a spectral type of A0, and has an apparent visual magnitude which varies between 2.84 and 2.98, with a period of 5.47 days. It is a chemically peculiar star with a strong magnetic field, about 5,000 times as strong as the Earth's, and is also classified as an Ap/Bp star. Its atmosphere has overabundances of some elements, such as silicon, mercury, and europium. This is thought to be due to some elements sinking down into the star under the force of gravity while others are elevated by radiation pressure. This star is the prototype of a class of variable stars, the so-called α2 Canum Venaticorum variables. The strong magnetic field of these stars is believed to produce starspots of enormous extent. Due to these starspots the brightness of α2 Canum Venaticorum stars varies considerably during their rotation.
α1 Canum Venaticorum.
α1 Canum Venaticorum is a F-type main sequence star. It is considerably fainter than its companion and has an apparent visual magnitude of approximately 5.60.
Namesakes.
"Cor Caroli" was a United States Navy Crater class cargo ship named after the star.
Cor Caroli is a yacht with which Captain Georgi Georgiev made a journey around the world alone.


Nu Persei

ν Persei, Latinized as Nu Persei, is a single star and a suspected variable in the northern constellation of Perseus. It has a yellow-white hue and is visible to the naked eye with an apparent visual magnitude of 3.80. This object is located approximately 560 light-years from the Sun based on parallax but is drifting closer with a radial velocity of −12 km/s.
This object is a highly luminous bright giant star with a stellar classification of F5II. It has five times the mass of the Sun but has expanded to around 21 times the Sun's radius. The star has a relatively high rotation rate, spinning with a projected rotational velocity of 48.9 km/s. It is radiating 604 times the luminosity of the Sun from its enlarged photosphere at an effective temperature of 6,300 K.
Several visual companions beside the primary have been recorded. B, with magnitude 12.1 and separation 31.6", has its own companion, E, with magnitude 14.3 and separation 7.7". Additionally, C has magnitude 13.2 and separation 55.7", and D has magnitude 13.8 and separation 22.8".


Gamma Draconis

Gamma Draconis (γ Draconis, abbreviated Gamma Dra, γ Dra), formally named Eltanin , is a star in the northern constellation of Draco. Contrary to its gamma-designation (historically third-ranked), it is the brightest star in Draco at magnitude 2.4, outshining Beta Draconis by nearly half a magnitude and Alpha Draconis by over a magnitude.
Gamma Draconis is at a distance of from the Sun, as determined by parallax measurements from the Hipparcos astrometry satellite. In 1728, while unsuccessfully attempting to measure the parallax of this star, the English astronomer James Bradley discovered the aberration of light resulting from the movement of the Earth. Bradley's discovery confirmed Copernicus' theory that the Earth revolved around the Sun.
In 1.5 million years, Gamma Draconis will pass within 28 light years of Earth. For a period, if its current absolute magnitude does not change, it will be the brightest star in the night sky, nearly as bright as Sirius is at present. It is by far the brightest star having a zenith above a point near London which led to its vaunting in these places as the "zenith star". From other locations it has a nearby bright, well-known star in Lyra in night sky; finding Vega, Gamma Draconis is the red star just north-northwest of it.
Properties.
Gamma Draconis is an evolved giant star with a stellar classification of K5 III. Since 1943, the spectrum of this star has served as one of the stable anchor points by which other stars are classified. It has 72% more mass than the Sun and it has expanded to around 48 times the Sun's girth. It is radiating about 471 times as much luminosity as the Sun from its outer atmosphere at an effective temperature of 3,930 K. This is cooler than the Sun, giving this star the orange-hued glow of a K-type star.
Gamma Draconis has six companions listed in double star catalogues. All were discovered by the American astronomer Sherburne Wesley Burnham. The closest may be physically associated and would be separated by about . The luminosity of this object suggests it is a red dwarf star. The others are all much more distant stars unrelated to Gamma Draconis.
Nomenclature.
"γ Draconis" (Latinised to "Gamma Draconis") is the star's Bayer designation.
It bore the traditional name "Eltanin" (or "Etamin", "Ettanin") derived from the Arabic التنين "At-Tinnin" 'The great serpent'. The name "Rastaban" was formerly used for Gamma Draconis, and the two terms share an Arabic root meaning "serpent" or "dragon". 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 "Eltanin" for this star on 21 August 2016 and it is now so entered in the IAU Catalog of Star Names.
Gamma Draconis, along with Beta Draconis, Mu Draconis, Nu Draconis, and Xi Draconis were "Al ʽAwāïd" "the Mother Camels", which was later known as the "Quinque Dromedarii".
In Chinese, (), meaning "Celestial Flail", refers to an asterism consisting of Gamma Draconis, Xi Draconis, Nu Draconis, Beta Draconis and Iota Herculis. Consequently, the Chinese name for Gamma Draconis itself is (, .)
Namesake.
USS "Etamin" was a United States Navy Crater class cargo ship named after the star.


NGC 209

NGC 209 is a lenticular galaxy located approximately 175 million light-years from the Solar System in the constellation Cetus. It was discovered on October 9, 1885 by Francis Leavenworth.


NGC 287

NGC 287 is a lenticular galaxy in the constellation Pisces. It was discovered on November 22, 1827 by John Herschel.


NGC 6248

NGC 6248 is a barred spiral galaxy in the constellation Draco. It was discovered on August 11, 1885 by the American astronomer Lewis A. Swift. The galaxy is located approximately 52 million light years away from earth with an approximate diameter of 47,000 light-years.


NGC 3554

NGC 3554 is an elliptical galaxy in the constellation Ursa Major. It was discovered in December 1827 by John Herschel.


Tau2 Lupi

Tau2 Lupi, Latinized from τ2 Lup, is a binary star system in the constellation Lupus. It is visible to the naked eye with a combined apparent visual magnitude of 4.34. Based upon an annual parallax shift of 10.22 mas as seen from Earth, it is located around 319 light years from the Sun. The two components orbit each other with a period of 26.2 years and a high eccentricity of 0.94. The brighter component is a magnitude 4.93 subgiant star with a stellar classification of F4 IV. Its companion is an A-type star with visual magnitude 5.55 and class A7:.


36 Cancri

36 Cancri is a star in the southern part of the zodiac constellation of Cancer, located around 501 light years away from the Sun. It has the Bayer designation c Cancri; "36 Cancri" is the Flamsteed designation. This object is a visible to the naked eye as a faint, white-hued star with an apparent visual magnitude of 5.92. It is moving further from the Earth with a heliocentric radial velocity of +16 km/s.
This is an ordinary A-type main-sequence star with a stellar classification of A3 V, which indicates it is generating energy through hydrogen fusion at its core. It has a projected rotational velocity of 44 km/s, with 2.66 times the mass of the Sun and double the Sun's radius. The star is radiating 93 times the Sun's luminosity from its photosphere at an effective temperature of 8,472 K.


Hercules A

Hercules A is a bright astronomical radio source within the vicinity of the constellation Hercules corresponding to the galaxy 3C 348.
Observation.
During a survey of bright radio sources in the mid-20th century, astronomers found a very bright radio source in the constellation Hercules. The radio source is strongest in the middle range frequency and emits synchrotron radiation, suggesting the source of radio emission may be gravitational interaction. In 1959, astronomers from the Radio Astronomy Group (later the Cavendish Astrophysics Group) detected the radio source using the Cambridge Interferometer of the Cavendish Observatory in Cambridge University in United Kingdom, including it in the Third Cambridge Catalogue of Radio Sources (3C) as 3C 348, the 348th object detected by the survey.
Characteristics.
Galaxy.
The galaxy, 3C 348, is a supergiant elliptical galaxy. It is classified as type E3 to E4 of the updated Hubble–de Vaucouleurs extended galaxy morphological classification scheme. Little else is known about the galaxy.
3C 348, the galaxy at the image center, appears to be a relatively normal elliptical galaxy in visible light. When imaged in radio waves, however, plasma jets over one million light years long appear. Detailed analyses indicate that the galaxy is actually over 1,000 times more massive (approx. 10 solar masses) than our Milky Way Galaxy, and the central black hole is nearly 1,000 times more massive (approx. 4 billion solar masses) than the black hole at our Milky Way's center, one of the largest known. The physics that creates the jets is poorly understood, with a likely energy source being matter ejected perpendicular to the accretion disc of the central black hole.


58 Eridani

58 Eridani is a main-sequence star in the constellation Eridanus. It is a solar analogue, having similar physical properties to the Sun. The star has a relatively high proper motion across the sky, and it is located about 43 light years distant. It is a probable member of the IC 2391 moving group of stars that share a common motion through space.
Characteristics.
This is a BY Draconis variable with the designation IX Eridani, which ranges in magnitude from 5.47 down to 5.51 with a period of 11.3 days. The X-ray emissions from this star's corona indicate an age of less than a billion (109) years, compared to 4.6 billion for the Sun, so it is still relatively young for a star of its mass. Starspot activity has also been detected, which varies from year to year.
A circumstellar disc of dust particles has been detected
in orbit around 58 Eridani.


NGC 3256

NGC 3256 is a peculiar galaxy formed from the collision of two separate galaxies in the constellation of Vela. NGC 3256 is located about 100 million light years away and belongs to the Hydra-Centaurus supercluster complex. NGC 3256 provides a nearby template for studying the properties of young star clusters in tidal tails. The system hides a double nucleus and a tangle of dust lanes in the central region. The telltale signs of the collision are two extended luminous tails swirling out from the galaxy. The tails are studded with a particularly high density of star clusters. NGC 3256 is the most luminous galaxy in the infrared spectrum located within z 0.01 from Earth.
Characteristics.
Nuclei.
NGC 3256 has double nuclei: the northern and southern nucleus, separated by 5", which at the distance of NGC 3256 corresponds to 850 pc. The nuclei are clearly visible in radiowaves and mid infrared, but the southern nucleus is hidden by dust lanes at the optical spectrum. The two nuclei will coalesce as the merger proceeds to its final stage. Lipari et al. note the presence of a third nucleus based on the presence of an obscured knot detected only at wavelengths λ ≥ 3.75 μm, which they suggest is a nuclear HII region.
There is evidence of an outflow of ionised gas from the northern nucleus with shocks which is attributed to a superwind powered by the starburst. Based on observations by Spitzer Space Telescope, and Chandra X-ray Observatory, Ohyana et al. suggested that the southern nucleus of NGC 3256 is a heavily absorbed low luminosity active galactic nucleus, with X-ray spectrum consistent with a typical Compton-thin Seyfert 2 galaxy.
HII regions.
Although NGC 3256 has seven large HII regions, a number small in comparison with other interacting galaxies, they are very luminous, with a total flux 85 times that of the Tarantula Nebula and they could host super star clusters. The HII regions coincide with X-ray emission regions, with possible sources being supernova remnants and X-ray binaries, which suggests the sources are in clusters with massive stars which may be initially embedded in HII regions. The HI mass of these features suggests they could be progenitors of globular clusters.
Tidal tails.
NGC 3256 features two tidal tails. The two tails account for approximately 75% of the HI emission of the galaxy, which, however, includes a central absorption feature. Michael Rubrock et al. found that the two tails have different colors, suggesting different stellar populations. The eastern tail has mean stellar population age determined to be 841+125−157 Myr and a larger percentage of mass belonging to the stellar population that was formed before the galaxy interaction. In the eastern tail were also detected several young (< 10 Myr), low mass objects with strong nebular emission, indicating a small, recent burst of star formation. The mean stellar population of the western tail was estimated to be 288+11−54 Myr and its light is dominated by stars formed after the interaction. The tails feature large numbers of star clusters, especially the western tail.
Nearby galaxies.
NGC 3256 belongs to a small group of galaxies which includes also the tidally disrupted NGC 3263 and NGC 3256C and roughly 15 more galaxies, as well as HI fragments. Some researchers have considered that NGC 3256 and NGC 3263 form two different groups but they are difficult to distinguish from each other spatially and two different group-finding algorithms applied to the same data catalogued the same galaxies in different groups. Among the features of the NGC 3256 group is a galaxy-sized intergalactic HI cloud known as the Vela Cloud, which as seen from Earth is not clearly associated with an individual galaxy but appears to be part of the group.
The NGC 3256 group belongs to the Hydra-Centaurus supercluster.


Gamma Comae Berenices

Gamma Comae Berenices, Latinized from γ Comae Berenices, is a single, orange-hued star in the northern constellation of Coma Berenices. It is faintly visible to the naked eye, having an apparent visual magnitude of 4.36. Based upon an annual parallax shift of 19.50 mas as seen from Earth, its distance can be estimated as around 167 light years from the Sun. The star is moving away from the Sun with a radial velocity of +3 km/s.
This is an evolved K-type giant star with a stellar classification of . The suffix notation indicates the star displays an overabundance of iron in its spectrum. It is most likely (91% chance) on the horizontal branch with an age of 2.7 billion years. If this is true, then it has an estimated 1.65 times the mass of the Sun and has expanded to nearly 12 times the Sun's radius. The star is radiating 58 times the Sun's luminosity from its enlarged photosphere at an effective temperature of around 4,652 K. Gamma Comae Berenices appears as part of the Coma Star Cluster, although it is probably not actually a member of this cluster.


Rho Capricorni

Rho Capricorni (ρ Cap, ρ Capricorni) is a binary star in the constellation Capricornus. Sometimes, this star is called by the name Bos, meaning "the cow" in Latin. In Chinese, (), meaning "Ox (asterism)", refers to an asterism consisting of β Capricorni, α2 Capricorni, ξ2 Capricorni, π Capricorni, ο Capricorni and ρ Capricorni. Consequently, the Chinese name for ρ Capricorni itself is (, .)
This system is visible to the naked eye with a combined apparent visual magnitude of +4.78. The pair orbit each other with a period of 278 years and an eccentricity of 0.91. Based upon an annual parallax shift of 33.04 mas as seen from the Earth, the system is located about 99 light years from the Sun. It is a thin disk population star system that made its closest approach to the Sun about 1.6 million years ago when it came within .
The primary member, component A, is a yellow-white hued, F-type subgiant with an apparent magnitude of 4.97 and a stellar classification of F2 IV. This star has 1.5 times the mass of the Sun and 1.3 times the Sun's radius. It is radiating 9 times as much luminosity of the Sun from its outer atmosphere at an effective temperature of 6,911 K. The companion, component B, has a visual magnitude of 6.88.


Eta Lyrae

Eta Lyrae, a name Latinized from η Lyrae, is a likely binary star system in the northern constellation of Lyra. It has the traditional name Aladfar and is faintly visible to the naked eye with an apparent visual magnitude of 4.43. The system is located at a distance of approximately 1,390 light years from the Sun based on parallax, but is drifting closer with a radial velocity of −8 km/s.
Nomenclature.
"η Lyrae" (Latinised to "Eta Lyrae") is the binary star's Bayer designation. Its designation as the "A" component of a double star, and of its two constituents as the "Aa" and "Ab" components, derives from the convention used by the Washington Multiplicity Catalog (WMC) for multiple star systems, and adopted by the International Astronomical Union (IAU).
'BD +38 3491' is the 'B' component's designation in the Bonner Durchmusterung astrometric star catalogue.
Eta Lyrae bore the traditional name "Aladfar", from the Arabic "الأظفر" "al-ʼuẓfur" "the talons (of the swooping eagle)", a name it shares with Mu Lyrae (though the latter is typically spelled "Alathfar"). The Working Group on Star Names (WGSN) has approved the name "Aladfar" for the Aa component of the system (the primary component of Eta Lyrae).
Properties.
The suspected radial velocity variations of this star in 1938 led to it being incorrectly classified as a Beta Cephei-type star, although there was some early disagreement about the variation. In 1951, J. A. Pearce and R. M. Petrie also noted that the star appeared to have a variable radial velocity. It was announced as a binary system by H. A. Abt and S. G. Levy in 1978, who listed it as a single-lined spectroscopic binary, albeit with marginal elements. The putative components have an orbital period of 56 days with an eccentricity (ovalness) of 0.5 and a small radial velocity variation of .
The visible component of this system is a massive B-type star with a stellar classification of B2.5IV. It is around 23 million years old with ten times the mass of the Sun and a low rotational velocity. The star is radiating around 19,525 times the luminosity of the Sun from its photosphere at an effective temperature of 19,525 K. A magnetic field has been detected with an average quadratic field strength of .
The magnitude 8.58 star BD +38 3491 forms a visual companion to this pair. It is designated Eta Lyrae B in the Washington Double Star Catalog, and is located at an angular separation of along a position angle of 81°, as of 2017.


Kappa Normae

Kappa Normae, Latinized from κ Normae, is a solitary, yellow hued star in the southern constellation of Norma. Its apparent magnitude is 4.94, which is bright enough to be faintly visible to the naked eye. Based upon an annual parallax shift of as seen from Earth, the system is located about 440 light years from the Sun. It is drifting closer with a radial velocity of 13.5 km/s.
This is an evolved giant star with a stellar classification of G8III that has swollen and cooled off the main sequence. At present it has 22 times the radius of the Sun. It shines with a luminosity approximately 226 times that of the Sun and has an effective temperature of 4,787 K.


Kappa2 Coronae Australis

Kappa2 Coronae Australis is a star in the southern constellation of Corona Australis. It is visible to the naked eye as a dim, blue-white hued star with an apparent visual magnitude of 5.67. The distance to this star is approximately 700 light years based on parallax. The radial velocity is poorly constrained, but the star appears to be moving closer with a radial velocity of around −15 km/s.
This object is a late B-type main-sequence star with a stellar classification of B9V. It is radiating 460 times the luminosity of the Sun from its photosphere at an effective temperature of 9,844 K. Kappa2 Coronae Australis forms a visual double star with Kappa1 Coronae Australis, also known as "HR 6952". 1 and 2 are located at 21.4 arcminutes from each other. The double is only in the line of sight, however, as Kappa1 is much more distant than the dimmer and closer Kappa2.


NGC 2899

NGC 2899 is a planetary nebula in the constellation Vela at a distance of nearly 6500 light years which lies in a moderate rich star zone. It was discovered by John Herschel in 1835.


NGC 6027e

NGC 6027e is a tidal tail of NGC 6027, not an individual galaxy, that is part of Seyfert's Sextet, a compact group of galaxies, which is located in the constellation Serpens.


Tau Herculis

Tau Herculis, a name Latinized from τ Herculis, is a variable star in the northern constellation of Hercules. It has a blue-white hue and is visible to the naked eye at night with an apparent visual magnitude that fluctuates around 3.91. The star is located at a distance of approximately 307 light years from the Sun based on parallax, but it is drifting closer with a radial velocity of −16 km/s.
The stellar classification of Tau Hercules is B5 IV, and it serves as a standard spectrum in the modern Morgan–Keenan (MK) classification. It is estimated to be just 26 million years old with a relatively low projected rotational velocity of 32 km/s. Slowly rotating B-type stars are often chemically peculiar, so the mostly normal spectra of this star suggests we may be viewing it from near pole-on. The abundance of most heavier elements in this star are about 85% of those in the Sun. The star has four times the mass of the Sun and around 3.8 times the Sun's radius. On average, it is radiating 574 times the luminosity of the Sun from its photosphere at an effective temperature of 15,615 K.
During the Hipparcos mission, Tau Hercules was discovered to be a variable star of the slowly pulsating B-type. These are mid-B main sequence stars that vary with a period of about a day; the brightness of Tau Hercules varies by 0.03 magnitude over a period of  days. The radial velocity of the star varies at a different rate than the photometric period, with the object showing both radial and non-radial pulsation modes.
Historical significance and etymology.
Tau Herculis is located within 1° of the precessional path traced across the celestial sphere by the Earth's North pole. It could have served the northern pole star around the year 7400 BCE, a phenomenon which is expected to reoccur in the year 18,400 due to precession.
Its traditional name, "Rukbalgethi Shemali", is of Arabic origin and shares certain etymological characteristics with the stars Ruchbah and Zubeneschamali, signifying Hercules' "northern knee".
In Chinese, (), meaning "Seven Excellencies", refers to an asterism consisting of τ Herculis, 42 Herculis, φ Herculis, χ Herculis, ν1 Boötis, μ1 Boötis and δ Boötis. Consequently, the Chinese name for τ Herculis itself is (, .)


NGC 5837

NGC 5837 is a barred spiral galaxy in the constellation Boötes. It was discovered on 19 June 1887 by Lewis A. Swift.
Supernovae.
A Type Ia Supernova, SN 2014ac, was discovered 9 March 2014, and on 16 June 2015, a Type IIN Supernova, SN 2015z, was discovered.


NGC 2527

NGC 2527 (also catalogued as "NGC 2520") is an open cluster in the constellation Puppis. It was discovered by William Herschel on December 9, 1784. The cluster was also observed by John Herschel on January 7, 1831. He also observed it on February 5, 1837, identifying it as a different object, which was catalogued as NGC 2520. It is a poor cluster and with no central concentration, with Trumpler class III1p.
The core radius of the cluster is 1 parsec (3.3 light years), while the tidal radius is 5.1 parsecs (17 light years) and represents the average outer limit of NGC 2527, beyond which a star is unlikely to remain gravitationally bound to the cluster core.
37 stars, probable members of the cluster, are located within the central part of the cluster and 96 probable members are located within the angular radius of the cluster. The brightest star members are A-type stars, with the brightest being an A3 star with magnitude 9.38. In the cluster has been detected one white dwarf, with mass . Its age is estimated to be years and the progenitor star has initial mass circa 3.1 . The turn-off mass of the cluster is at 2.8 . The metallicity of the cluster is -0.01, similar to the solar one.
NGC 2527 lies 3.8 degrees south of Rho Puppis and can be seen with 50mm binoculars as a moderately large, bright patch of haze, with no stars visible with direct vision.


NGC 6569

NGC 6569 is a globular cluster in the constellation Sagittarius. It has an apparent magnitude of about 9.5, and an apparent diameter of 7 arc minutes, and class VIII with stars of magnitude 15 and dimmer. It is about 2 degrees south east of Gamma2 Sagittarii. The globular cluster was discovered in 1784 by the astronomer William Herschel with his 18.7-inch telescope and was catalogued later in the New General Catalogue.


Gamma Delphini

Gamma Delphini, which is Latinized from γ Delphini, is a wide binary star system in the northern constellation of Delphinus. The star marks one corner of the asterism "Job's Coffin". The pair can be split with a modest amateur telescope and have been described as "one of the prettier pairs in the sky", with their contrasting colors said to be orange and lime in appearance. Together, the system is visible to the naked eye with a combined apparent visual magnitude of 3.87.
Space motion.
The system is located at a distance of 115 light years from the Sun based on parallax, but is drifting closer with a radial velocity of −7 km/s. It is a member of the thin disk population, and is a proposed member of the Wolf 630 moving group.
This star was found to be a double by Christian Mayer and later observed by William Herschel on Sept 27th, 1779. It was later included as STF 2727 in the catalogue compiled by F. G. W. Struve and can be found under this name in the Washington Double Star Catalog. At the time, the components had an angular separation of along a position angle (PA) of 280°. As of 2019, they are separated by with a PA of 265°. The fainter component, designated γ1 Delphini, is of apparent magnitude 5.03. Its companion is a magnitude 4.360 star designated γ2 Delphini. A fit of orbital elements to the available positional data provides a period of 3,249 years with a high eccentricity (ovalness) of 0.88. Their physical separation ranges from roughly 40 out to .
Physical properties.
The stellar classification of γ1 Delphini is F7V, which matches an F-type main-sequence star with a yellow-white hue. It is about 1.8 billion years old and is spinning with a projected rotational velocity of 7.8 km/s. The star has 1.6 times the mass and 2.6 times the radius of the Sun. It is radiating 10 times the Sun's luminosity from its photosphere at an effective temperature of 6,295 K.
The brighter component, γ2 Delphini, has an orange hue with a class of K1IV. Being the more massive star of the pair, it is the more evolved star and is currently on the subgiant branch. It has double the mass of the Sun but has expanded to over eight times the Sun's radius. The star is radiating 33 times the luminosity of the Sun at 4,798 K. It is spinning with a projected rotational velocity of 3.6 km/s. The star displays a radial acceleration with a periodicity of 1.44 years, which may be the effect of an orbiting companion.
The system is a source of X-ray emission with high probability.
Possible planetary system.
In 1999, the presence of a planetary companion was inferred around Gamma2 Delphini as one possible explanation for the radial velocity variations. Such a planet would have a minimum mass of 0.7 Jupiter masses, orbital period of 1.44 years and separation of nearly 1.5 astronomical units (almost the orbital separation of Mars from the Sun). The planetary candidate has not been confirmed. McDonald Observatory researches have set mass limits for potential planetary companions in orbit around the star Gamma2 Delphini.


56 Orionis

56 Orionis is a single, variable star in the equatorial constellation of Orion. It has an orange hue and is faintly visible to the naked eye with an apparent visual magnitude that fluctuates around 4.76. The star is located at a distance of approximately 1,130 light years from the Sun based on parallax. It is drifting further away with a radial velocity of +11 km/s. The star has a peculiar velocity of relative to its neighbors, and may be a runaway star.
This object is a bright giant star with a stellar classification of K2-IIb. It is a suspected variable star of unknown type with a brightness that has been measured varying from 4.73 down to 4.78. The star is about 61 million years old with 6.4 times the mass of the Sun and is spinning with a projected rotational velocity of 3.5. Having exhausted the supply of hydrogen at its core, the star has expanded to 92 times the radius of the Sun. It is radiating 2,547 times the Sun's luminosity from its enlarged photosphere at an effective temperature of 4,270 K.
It has one reported visual companion, designated component B, with magnitude 13.5 and angular separation .


HD 20644

HD 20644 is a suspected binary star system in the constellation Aries. It has an orange hue and is visible to the naked eye with an apparent visual magnitude of 4.47. The system is located at a distance of approximately 540 light years from the Sun based on parallax, but is drifting closer with a radial velocity of −3 km/s.
The visible component is an aging giant star with a stellar classification of K3IIIa Ba0.5, where the suffix notation indicates this is a mild barium star. The atmosphere of this star is enriched with s-process elements that are posited to have been transferred from what is now a white dwarf companion when it evolved along the asymptotic giant branch (AGB). Alternatively, this star may itself be on the AGB.
HD 20644 is about 350 million years old with three times the mass of the Sun and is spinning with a projected rotational velocity of 1.4 km/s. With the supply of hydrogen at its core exhausted, it has expanded to 75 times the Sun's radius. It is radiating 1,292 times the luminosity of the Sun from its photosphere at an effective temperature of 3,987 K.


Kepler-76b

Kepler-76b is a gas giant with the mass about two times of Jupiter.
It is a Hot Jupiter that orbits its star every 1.5 days. It was confirmed with the Trans-Atlantic Exoplanet Survey and the SOPHIE échelle spectrograph.
Detection.
The planet was discovered by observing the amount of stellar flux reaching the Earth. The existence of the planet was confirmed by also observing the reflected starlight from the planet, the shape of the star due to gravitational tug from the planet and radial velocity method. Finally, part of the planet was found transiting the parent star with secondary occultation also being detected.
It is the first planet detected using Einstein's special relativity.
Characteristics.
Kepler-76b is slightly denser than Jupiter indicating that it is not a puffy planet. Nonetheless, it is very hot with measured dayside temperature of 2830 K. It also exhibits a strong winds and variable clouds in the atmosphere.


Rho Cancri

The Bayer designation ρ Cancri (Rho Cancri) is shared by two stars in the constellation Cancer:


D Carinae

The Bayer designations d Carinae and D Carinae are distinct.


XO-4

XO-4 is a star located approximately 896 light-years away from Earth in the Lynx constellation. It has a magnitude of about 11 and cannot be seen with the naked eye but is visible through a small telescope. A search for a binary companion star using adaptive optics at MMT Observatory was negative.
The star XO-4 is named Koit. The name was selected in the NameExoWorlds campaign by Estonia, during the 100th anniversary of the IAU. Koit is Estonian for "dawn", and was named for a character in a folk tale written by Friedrich Robert Faehlmann.
Planetary system.
One known exoplanet, XO-4b, which is classified as a hot jupiter, orbits XO-4. This exoplanet was discovered in 2008 by the XO Telescope project using the transit method. It has been named Hämarik, meaning "dusk", and referring to a character from the same Faehlmann story featuring Koit.


NGC 2070

NGC 2070 (also known as Caldwell 103) is a large open cluster and candidate super star cluster forming the heart of the bright region in the centre-south-east of the Large Magellanic Cloud. It is at the centre of the Tarantula Nebula and produces most of the energy that makes the latter's gas and dust visible. Its central condensation is the star cluster R136, one of the most energetic star clusters known. Among its stars are many of great dimension, including the second most massive star known, R136a1, at 215 and 6.16 million .


32 Persei

32 Persei is a single star located 149 light years away from the Sun in the northern constellation of Perseus. It has the Bayer designation of l Persei, while "32 Persei" is the Flamsteed designation. This object is visible to the naked eye as a faint, white-hued star with an apparent visual magnitude of 4.96. It is moving closer to the Earth with a heliocentric radial velocity of −9 km/s, and is a member of the Sirius supercluster: a stream of stars that share a common motion through space.
This is an ordinary A-type main-sequence star with a stellar classification of A3V. It is around 125 million years old with a high rate of spin, showing a projected rotational velocity of 144 km/s. The star has double the mass of the Sun and 1.8 times the Sun's radius. It is radiating 21 times the luminosity of the Sun from its photosphere at an effective temperature of 8,872 K.


NGC 970

NGC 970 is an interacting galaxy pair in the constellation Triangulum. It is estimated to be 471 million light-years from the Milky Way and has a diameter of approximately 100,000 ly. The object was discovered on September 14, 1850 by Bindon Blood Stoney.


Pi Coronae Borealis

Pi Coronae Borealis, Latinized from π Coronae Borealis, is a solitary, orange-hued star in the northern constellation of Corona Borealis. Its apparent magnitude is 5.58, which is bright enough to be faintly visible to the naked eye. Based upon an annual parallax shift of 13.40 mas as measured from Earth, it is located about 243 light years from the Sun. The star is moving closer to the Sun with a radial velocity of −5 km/s. It is most likely (98% chance) a member of the thin disk population.
This is an evolved G-type giant star with a stellar classification of G9 III:, where the ':' indicates some uncertainty about the classification. (Bartkevicius and Lazauskaite (1997) classify it as K0 III.) The star has 1.61 times the mass of the Sun and has expanded to about 10 times the Sun's radius. The abundance of iron is lower than in the Sun: the star is considered metal deficient. It is around 4.6 billion years old and is radiating 39 times the Sun's luminosity from its enlarged photosphere at an effective temperature of 4,667 K.


46 Ceti

46 Ceti is a single star in the equatorial constellation of Cetus. It is visible to the naked eye with an apparent visual magnitude of 4.9. The distance to this star, as determined from an annual parallax shift of , is about 273 light years. It is moving closer to the Earth with a heliocentric radial velocity of −23 km/s, and is expected to come as close as in 2.2 million years.
At the age of about four billion years, this is an evolved K-type giant star with a stellar classification of . The suffix notation CN0.5 indicates a mild overabundance of cyanogen in the stellar atmosphere. It has 1.38 times the mass of the Sun and has expanded to 19 times the Sun's radius. The star is radiating 132 times the Sun's luminosity from its enlarged photosphere at an effective temperature of 4,316 K. The projected rotational velocity is too small to be measured.


NGC 3344

NGC 3344 is a relatively isolated barred spiral galaxy located 22.5 million light years away in the constellation Leo Minor. This galaxy belongs to the group known as the Leo spur, which is a branch of the Virgo Supercluster. NGC 3344 has the morphological classification (R)SAB(r)bc, which indicates it is a weakly barred spiral galaxy that exhibits rings and moderate to loosely wound spiral arms. There is both an inner and outer ring, with the prominent arms radiating outward from the inner ring and the slightly elliptical bar being situated inside. At the center of the bar is an HII nucleus with an angular diameter of about 3″. NGC 3344 hosted supernova SN2012fh, which was shown to likely be a Type Ib or Type Ic.


Sigma3 Cancri

Sigma3 Cancri (σ3 Cancri) is a solitary, yellow-hued star in the zodiac constellation of Cancer. With an apparent visual magnitude of +5.24, it is a dim star that is visible to the naked eye. Based upon an annual parallax shift of 11.03 mas as seen from Earth, it is located around 296 light years from the Sun. The star's proper motion makes it a candidate for membership in the IC 2391 supercluster.
This is an evolved, G-type giant star with a stellar classification of G9 III. At the estimated age of 420 million years it is a red clump star on the horizontal branch, which indicates it is generating energy through helium fusion at its core. Sigma3 Cancri has 2.8 times the mass of the Sun and has expanded to 10.3 times the Sun's radius. It is radiating 72 times the solar luminosity from its photosphere at an effective temperature of 5,170 K.


Upsilon Hydrae

The Bayer designation υ Hydrae (Latinised to Upsilon Hydrae; abbreviated υ Hya, Ups Hya) is shared by two stars in the constellation of Hydra:


Kepler-90h

Kepler-90h (also known by its Kepler Object of Interest designation "KOI-351.01") is an exoplanet orbiting within the habitable zone of the early G-type main sequence star Kepler-90, the outermost of eight such planets discovered by NASA's Kepler spacecraft. It is located about 2,840 light-years (870 parsecs), from Earth in the constellation Draco. The exoplanet was found by using the transit method, in which the dimming effect that a planet causes as it crosses in front of its star is measured.
Characteristics.
Physical characteristics.
Kepler-90h is a gas giant with no solid surface. Its equilibrium temperature is . It is around 1.2 times as massive and around 1.01 times as large as Jupiter. This makes it very similar to Jupiter, in terms of mass and radius.
Orbit.
Kepler-90h orbits its host star about every 331.6 days at a distance of 1.01 astronomical units, very similar to Earth's orbital distance from the Sun (which is 1 AU).
Habitability.
Kepler-90h resides in the circumstellar habitable zone of the parent star. The exoplanet, with a radius of 1.01 , is too large to be rocky, and because of this the planet itself may not be habitable. Hypothetically, large enough moons, with a sufficient atmosphere and pressure, may be able to support liquid water and potentially life.
For a stable orbit the ratio between the moon's orbital period "P"s around its primary and that of the primary around its star "P"p must be < 1/9, e.g. if a planet takes 90 days to orbit its star, the maximum stable orbit for a moon of that planet is less than 10 days. Simulations suggest that a moon with an orbital period less than about 45 to 60 days will remain safely bound to a massive giant planet or brown dwarf that orbits 1 AU from a Sun-like star. In the case of Kepler-90h, this would be practically the same to have a stable orbit.
Tidal effects could also allow the moon to sustain plate tectonics, which would cause volcanic activity to regulate the moon's temperature and create a geodynamo effect which would give the satellite a strong magnetic field.
To support an Earth-like atmosphere for about 4.6 billion years (the age of the Earth), the moon would have to have a Mars-like density and at least a mass of 0.07 . One way to decrease loss from sputtering is for the moon to have a strong magnetic field that can deflect stellar wind and radiation belts. NASA's Galileo's measurements hints large moons can have magnetic fields; it found that Jupiter's moon Ganymede has its own magnetosphere, even though its mass is only 0.025 .
Host star.
The planet orbits a (G-type) Kepler-90, its host star. The star is 1.2 times as massive as the Sun and is 1.2 times as large as the Sun. It is estimated to be 2 billion years old, with a surface temperature of 6080 K. In comparison, the Sun is about 4.6 billion years old and has a surface temperature of 5778 K.
The star's apparent magnitude, or how bright it appears from Earth's perspective, is 14. It is too dim to be seen with the naked eye, which typically can only see objects with a magnitude around 6 or less.
Discovery.
In 2009, NASA's Kepler spacecraft was completing observing stars on its photometer, the instrument it uses to detect transit events, in which a planet crosses in front of and dims its host star for a brief and roughly regular period of time. In this last test, Kepler observed stars in the Kepler Input Catalog, including Kepler-90; the preliminary light curves were sent to the Kepler science team for analysis, who chose obvious planetary companions from the bunch for follow-up at observatories. Observations for the potential exoplanet candidates took place between 13 May 2009 and 17 March 2012. After observing the respective transits, which for Kepler-90h occurred roughly every 331 days (its orbital period), it was eventually concluded that a planetary body was responsible for the periodic 331-day transits. The discovery, was announced on November 12, 2013.


Delta Microscopii

δ Microscopii, Latinised as Delta Microscopii, is a faint, orange hued binary star system in the constellation Microscopium, marking the eyepiece end of the "microscope". It is just visible to the naked eye with an apparent visual magnitude of +5.68. Based upon an annual parallax shift of 10.82 mas as seen from the Earth, it is roughly 300 light years from the Sun. At that distance, the visual magnitude is diminished by an extinction factor of 0.142 due to interstellar dust.
This is a single-lined spectroscopic binary with an orbital period of 4.4 years and an eccentricity of 0.2. The visible component is an evolved K-type giant star with a stellar classification of K0/1 III. It is currently on the horizontal branch and thus is generating energy through helium fusion at its core. Delta Microscopii has nearly twice the mass of the Sun and has expanded to 11 times the Sun's radius. The star is radiating 57 times the Sun's luminosity from its enlarged photosphere at an effective temperature of 4,805 K.


HD 88809

HD 88809 is a star in a double star system in the constellation Antlia. The primary is an orange giant of spectral type K1III. Located around 480 light-years distant, it shines with a luminosity approximately 124 times that of the Sun and has a surface temperature of 4607 K. It has an apparent magnitude of 5.9, while the secondary star has a magnitude of 13.