Astronomy:Alpha Comae Berenices

From HandWiki
Short description: Star in the constellation Coma Berenices
α Comae Berenices
Map of the constellation Coma Berenices
Red circle.svg
α Comae Berenices (circled) in the constellation Coma Berenices
Observation data
Equinox J2000.0]] (ICRS)
Constellation Coma Berenices
Right ascension  13h 09m 59.285s[1]
Declination +17° 31′ 46.04″[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 color index −0.06[5]
B−V color index 0.45[5]
V−R color index 0.2[6]
R−I color index 0.2[6]
Astrometry
Radial velocity (Rv)−17.7±0.9[6] km/s
Proper motion (μ) RA: −433.13±0.70[1] mas/yr
Dec.: 141.24±0.51[1] mas/yr
Parallax (π)56.10 ± 0.89[1] mas
Distance58.1 ± 0.9 ly
(17.8 ± 0.3 pc)
Absolute magnitude (MV)3.82[7]
Orbit[8]
Period (P)25.8696±0.008219 yr
Semi-major axis (a)0.67144±0.00033″
Eccentricity (e)0.51060±0.00061
Inclination (i)90.0501±0.0062°
Longitude of the node (Ω)12.2272±0.0098°
Periastron epoch (T)57056.84±0.36
Argument of periastron (ω)
(secondary)		100.563±0.026°
Details
A
Mass1.237[9] M☉
Luminosity1.72[10] L☉
Surface gravity (log g)4.19[11] cgs
Temperature6,365[11] K
Metallicity [Fe/H]−0.23[11] dex
B
Mass1.087[9] M☉
Luminosity1.75[10] L☉
Temperature6,378[10] K
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

Alpha Comae Berenices (α Comae Berenices, abbreviated Alpha Com, α Com) is a binary star in the constellation of Coma Berenices (Berenice's Hair), 17.8 parsecs (58 ly) 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 /ˈdaɪədɛm/, 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".[citation needed] 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, 太微左垣 (Tài Wēi Zuǒ Yuán), 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 太微左垣五 (Tài Wēi Zuǒ Yuán wǔ, English: the Fifth Star of Left Wall of Supreme Palace Enclosure.),[19] representing 東上將 (Dōngshǎngjiāng), 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

  1. ↑ 1.0 1.1 1.2 1.3 1.4 van Leeuwen, F. (2007). "Validation of the new Hipparcos reduction". Astronomy and Astrophysics 474 (2): 653–664. doi:10.1051/0004-6361:20078357. Bibcode: 2007A&A...474..653V. http://www.aanda.org/articles/aa/abs/2007/41/aa8357-07/aa8357-07.html.  Vizier catalog entry
  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. ↑ Entry 13100+1732, Sixth Catalog of Orbits of Visual Binary Stars , United States Naval Observatory. Accessed on line September 3, 2008.
  4. ↑ Diadem , Jim Kaler, Stars. Accessed on line September 3, 2008.
  5. ↑ 5.0 5.1 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. ↑ 6.0 6.1 6.2 6.3 NSV 6116 -- Variable Star, database entry, SIMBAD. Accessed on line September 3, 2008.
  7. ↑ Reiners, Ansgar (January 2006), "Rotation- and temperature-dependence of stellar latitudinal differential rotation", Astronomy and Astrophysics 446 (1): 267–277, doi:10.1051/0004-6361:20053911, Bibcode: 2006A&A...446..267R 
  8. ↑ 8.0 8.1 Muterspaugh, Matthew W. et al. (2015). "Predicting the α Comae Berenices Time of Eclipse: How 3 Ambiguous Measurements out of 609 Caused a 26 Year Binary's Eclipse to be Missed". The Astronomical Journal 150 (5): 140. doi:10.1088/0004-6256/150/5/140. Bibcode: 2015AJ....150..140M. 
  9. ↑ 9.0 9.1 Pavlovic, R.; Todorovic, N. (2005). "Orbits of Seven Edge-On Visual Double Stars". Serbian Astronomical Journal 170 (170): 73–78. doi:10.2298/SAJ0570073P. Bibcode: 2005SerAJ.170...73P. 
  10. ↑ 10.0 10.1 10.2 Ten Brummelaar, Theo; Mason, Brian D.; McAlister, Harold A.; Roberts, Lewis C.; Turner, Nils H.; Hartkopf, William I.; Bagnuolo, William G. (2000). "Binary Star Differential Photometry Using the Adaptive Optics System at Mount Wilson Observatory". The Astronomical Journal 119 (5): 2403. doi:10.1086/301338. Bibcode: 2000AJ....119.2403T. 
  11. ↑ 11.0 11.1 11.2 Soubiran, Caroline; Le Campion, Jean-François; Brouillet, Nathalie; Chemin, Laurent (2016). "The PASTEL catalogue: 2016 version". Astronomy and Astrophysics 591: A118. doi:10.1051/0004-6361/201628497. Bibcode: 2016A&A...591A.118S. 
  12. ↑ HD 114378 -- Star in double system, database entry, SIMBAD, accessed on line September 3, 2008.
  13. ↑ HD 114379 -- Star in double system, database entry, SIMBAD, accessed on line September 3, 2008.
  14. ↑ 14.0 14.1 "Naming Stars". IAU.org. https://www.iau.org/public/themes/naming_stars/. 
  15. ↑ Hessman, F. V.; Dhillon, V. S.; Winget, D. E.; Schreiber, M. R.; Horne, K.; Marsh, T. R.; Guenther, E.; Schwope, A.; Heber, U. (2010). "On the naming convention used for multiple star systems and extrasolar planets". arXiv:1012.0707 [astro-ph.SR].
  16. ↑ "International Astronomical Union | IAU". https://www.iau.org/science/scientific_bodies/working_groups/280/. 
  17. ↑ "WG Triennial Report (2015-2018) - Star Names". p. 5. https://www.iau.org/static/science/scientific_bodies/working_groups/280/wg-starnames-triennial-report-2015-2018.pdf. 
  18. ↑ (in Chinese) 中國星座神話, written by 陳久金. Published by 台灣書房出版有限公司, 2005, ISBN:978-986-7332-25-7.
  19. ↑ (in Chinese) 香港太空館 - 研究資源 - 亮星中英對照表 , Hong Kong Space Museum. Accessed on line November 23, 2010.
  20. ↑ (in Chinese) English-Chinese Glossary of Chinese Star Regions, Asterisms and Star Name , 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 , United States Naval Observatory. Accessed on line September 3, 2008.

External links

Coordinates: Sky map 13h 09m 59.285s, +17° 31′ 46.04″



Retrieved from "https://handwiki.org/wiki/index.php?title=Astronomy:Alpha_Comae_Berenices&oldid=3426904"