Alpha Comae Berenices

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Template:Short description

α Comae Berenices
Template:Location mark
α Comae Berenices (circled) in the constellation Coma Berenices
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Coma Berenices
Right ascension Template:RA[1]
Declination Template:DEC[1]
Apparent magnitude (V) 4.29 to 4.35
(combined)[2]
A: 4.85 / B: 5.53[3]
Characteristics
Spectral type A: F5V / B: F5V
(binary star)[4]
U−B Template:Engvar −0.06[5]
B−V Template:Engvar 0.45[5]
V−R Template:Engvar 0.2[6]
R−I Template:Engvar 0.2[6]
Astrometry
Radial velocity (Rv)Template:Val[6] km/s
Proper motion (μ) RA: Template:Val[1] mas/yr
Dec.: Template:Val[1] mas/yr
Parallax (π)56.10±0.89 mas[1]
DistanceTemplate:Rnd ± Template:Rnd ly
(Template:Rnd ± Template:Rnd pc)
Absolute magnitude (MV)3.82[7]
Orbit[8]
Period (P)Template:Val yr
Semi-major axis (a)Template:Val″
Eccentricity (e)Template:Val
Inclination (i)Template:Val°
Longitude of the node (Ω)Template:Val°
Periastron epoch (T)Template:Val
Argument of periastron (ω)
(secondary)		Template:Val°
Details
A
Mass1.237[9] Template:Solar mass
Luminosity1.72[10] Template:Solar luminosity
Surface gravity (log g)4.19[11] cgs
Temperature6,365[11] K
Metallicity [Fe/H]Template:Val[11] dex
B
Mass1.087[9] Template:Solar mass
Luminosity1.75[10] Template:Solar luminosity
Temperature6,378[10] K
Metallicity [Fe/H]{{{metal_fe2}}} dex
Other designations
α Com, Alpha Comae Berenices, Alpha Com, 42 Comae Berenices, 42 Com, STF 1728, ADS 8804 , BD+18 2697, CCDM J13100+1732, GC 17833, Gliese 501, HIP 64241, IDS 13051+1803 AB, LTT 13802, NLTT 33105, PPM 129630, SAO 100443, WDS 13100+1732.[6][12][13]
A: HD 114378, HR 4968
B: HD 114379, HR 4969
Database references
SIMBADdata

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Alpha Comae Berenices (α Comae Berenices, abbreviated Alpha Com, α Com) is a binary star in the constellation of Coma Berenices (Berenice's Hair), Template:Convert away. It consists of two main sequence stars, each a little hotter and more luminous than the Sun.

Alpha Comae Berenices is said to represent the crown worn by Queen Berenice. The two components are designated Alpha Comae Berenices A (officially named Diadem Template:IPAc-en, the traditional name for the system)[14] and B.

Nomenclature

α Comae Berenices (Latinised to Alpha Comae Berenices) is the system's Bayer designation. The designations of the two components as Alpha Comae Berenices A and B derive from the convention used by the Washington Multiplicity Catalog (WMC) for multiple star systems, and adopted by the International Astronomical Union (IAU).[15]

The system bore the traditional names Diadem and Al Dafirah, the latter derived from the Arabic الضفيرة ađ̧-đ̧afīrah "the braid".Script error: No such module "Unsubst". In 2016, the International Astronomical Union organized a Working Group on Star Names (WGSN)[16] to catalogue and standardize proper names for stars. The WGSN decided to attribute proper names to individual stars rather than entire multiple systems.[17] It approved the name Diadem for the component Alpha Comae Berenices A on 1 February 2017 and it is now so included in the List of IAU-approved Star Names.[14]

In Chinese, Script error: No such module "Lang". (Script error: No such module "Lang".), meaning Left Wall of Supreme Palace Enclosure, refers to an asterism consisting of Alpha Comae Berenices, Eta Virginis, Gamma Virginis, Delta Virginis and Epsilon Virginis.[18] Consequently, the Chinese name for Alpha Comae Berenices itself is Script error: No such module "Lang". (Script error: No such module "Lang"., Template:Langx.),[19] representing Script error: No such module "Lang". (Script error: No such module "Lang".), meaning The First Eastern General.[20] 東上將 (Dōngshǎngjiāng), westernized into Shang Tseang, but that name was designated for "v Comae Berenices" by R.H. Allen and the meaning is "a Higher General".[21]

Properties

Although Alpha Comae Berenices bears the title "alpha", at magnitude 4.32 it is actually fainter than Beta Comae Berenices.

It is a binary star, with almost equal components of magnitudes 5.05 m and 5.08 m orbiting each other with a period of 25.87 years. The system, estimated to be 58 light-years distant, appears so nearly "edge-on" from the Earth that the two stars appear to move back-and-forth in a straight line with a maximum separation of only 0.7 arcsec. Eclipses are predicted to occur between the two components however they have not been successfully observed due to miscalculations of the time of eclipse.[8]

The mean separation between them is approximately 10 AU, about the distance between the Sun and Saturn.

The binary star has a visual companion, CCDM J13100+1732C, of apparent magnitude 10.2, located 89 arcseconds away along a position angle of 345°.[22]

Alpha Comae Berenicis forms an isosceles triangle with globular star clusters Messier 53 and NGC 5053. The apparent diameter of this triangle is a little more than one degree. The location of Alpha Comae Berenicis is westward (preceding) of both globular star clusters.

References

Template:Reflist

External links

Template:Sky Template:Stars of Coma Berenices

  1. ↑ a b c d e Cite error: Invalid <ref> tag; no text was provided for refs named van Leeuwen2007
  2. ↑ NSV 6116, database entry, New Catalogue of Suspected Variable Stars, the improved version, Sternberg Astronomical Institute, Moscow, Russia. Accessed on line September 3, 2008.
  3. ↑ Cite error: Invalid <ref> tag; no text was provided for refs named orb
  4. ↑ Diadem Template:Webarchive, Jim Kaler, Stars. Accessed on line September 3, 2008.
  5. ↑ a b HR 4968, database entry, The Bright Star Catalogue, 5th Revised Ed. (Preliminary Version), D. Hoffleit and W. H. Warren, Jr., CDS ID V/50. Accessed on line September 3, 2008.
  6. ↑ a b c d Cite error: Invalid <ref> tag; no text was provided for refs named sb0
  7. ↑ Cite error: Invalid <ref> tag; no text was provided for refs named Reiners2006
  8. ↑ a b Cite error: Invalid <ref> tag; no text was provided for refs named Muterspaugh2015
  9. ↑ a b Cite error: Invalid <ref> tag; no text was provided for refs named pavlovic
  10. ↑ a b c Cite error: Invalid <ref> tag; no text was provided for refs named brummelaar
  11. ↑ a b c Cite error: Invalid <ref> tag; no text was provided for refs named pastel
  12. ↑ Template:SIMBAD link, database entry, SIMBAD, accessed on line September 3, 2008.
  13. ↑ Template:SIMBAD link, database entry, SIMBAD, accessed on line September 3, 2008.
  14. ↑ a b Script error: No such module "citation/CS1".
  15. ↑ Script error: No such module "citation/CS1".
  16. ↑ Script error: No such module "citation/CS1".
  17. ↑ Script error: No such module "citation/CS1".
  18. ↑ Template:In lang 中國星座神話, written by 陳久金. Published by 台灣書房出版有限公司, 2005, Template:ISBN.
  19. ↑ Template:In lang 香港太空館 - 研究資源 - 亮星中英對照表 Template:Webarchive, Hong Kong Space Museum. Accessed on line November 23, 2010.
  20. ↑ Template:In lang English-Chinese Glossary of Chinese Star Regions, Asterisms and Star Name Template:Webarchive, Hong Kong Space Museum. Accessed on line November 23, 2010.
  21. ↑ Richard Hinckley Allen: Star Names — Their Lore and Meaning: Coma Berenices
  22. ↑ Entry 13100+1732, discoverer code STF1728, components AB-C, The Washington Double Star Catalog Template:Webarchive, United States Naval Observatory. Accessed on line September 3, 2008.
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