- Alpha Comae Berenices
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α Comae Berenices Observation data
Epoch J2000.0 Equinox J2000.0 (ICRS)Constellation Coma Berenices Right ascension 13h 09m 59.2766s[1] Declination +17° 31′ 45.953″[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[1] R−I color index 0.2[1] Astrometry Radial velocity (Rv) −17.7 ± 0.9[1] km/s Proper motion (μ) RA: −445.96[1] mas/yr
Dec.: 129.69[1] mas/yrParallax (π) 51.7 ± 5.7[6] mas Distance approx. 63 ly
(approx. 19 pc)Absolute magnitude (MV) 3 (combined)[7] Orbit[3] Period (P) 26.052 ± 0.013 years Semimajor axis (a) 0.67633 ± 0.00095″ Eccentricity (e) 0.5083 ± 0.0026 Inclination (i) 90.098 ± 0.051° Longitude of the node (Ω) 192.235 ± 0.047° Periastron epoch (T) B1989.2052 ± 0.0061 Argument of periastron (ω)
(secondary)280.121 ± 0.070° Other designations Database references SIMBAD data Alpha Comae Berenices (Alpha Com, α Com, α Comae Berenices) is a star in the constellation Coma Berenices (Berenice's Hair). Although it has the Bayer designation "alpha", at magnitude 4.32 it is actually fainter than Beta Comae Berenices. It has the traditional name Diadem. It is said to represent the crown worn by Queen Berenice. A name occasionally seen is Al Dafirah, from the Arabic الضفيرة ađ̧-đ̧afīrah "the braid".
In Chinese, 太微左垣 (Tài Wēi Zuǒ Yuán), meaning Left Wall of Supreme Palace Enclosure, refers to an asterism consisting of α Comae Berenices, η Virginis, γ Virginis, δ Virginis and ε Virginis.[10] Consequently, α Comae Berenices itself is known as 太微左垣五 (Tài Wēi Zuǒ Yuán wǔ, English: the Fifth Star of Left Wall of Supreme Palace Enclosure.),[11] representing 東上將 (Dōngshǎngjiāng), meaning The First Eastern General.[12] 東上將 (Dōngshǎngjiāng), westernized into Shang Tseang, but the name Shang Tseang was designated for "v Comae Berenices" by R.H. Allen and the meaning is "a Higher General" [13]
Contents
Properties
It is a binary star, with almost equal components of magnitudes 5.05m and 5.08m orbiting each other with a period of 25.87 years. The system, estimated to be 65 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. It is not known whether eclipses occur between the two components at periastron (minimum separation)—the only such passage since the determination of the orbit, in 1990, was not quantitatively followed by observers.
The mean separation between them is approximately 10 A.U., about the distance between the Sun and Saturn.
Visual companion
CCDM J13100+1732C Observation data
Epoch J2000.0 Equinox J2000.0 (ICRS)Constellation Coma Berenices Right ascension 13h 10m 00.4s[14] Declination +17° 31′ 48″[14] Apparent magnitude (V) 10.2[14] Position (relative to α Comae Berenices AB) Epoch of observation 1998 Angular distance 88.7″ [15] Position angle 345° [15] Other designations Database references SIMBAD data The binary star has a visual companion, CCDM J13100+1732C, of apparent magnitude 10.2, located 89 arcseconds away.[14][15]
References
- ^ a b c d e f g h NSV 6116 -- Variable Star, database entry, SIMBAD. Accessed on line September 3, 2008.
- ^ NSV 6116, database entry, New Catalogue of Suspected Variable Stars, the improved version, Sternberg Astronomical Institute, Moscow, Russia. Accessed on line September 3, 2008.
- ^ a b Entry 13100+1732, Sixth Catalog of Orbits of Visual Binary Stars, United States Naval Observatory. Accessed on line September 3, 2008.
- ^ Diadem, Jim Kaler, Stars. Accessed on line September 3, 2008.
- ^ 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.
- ^ GJ 501, database entry, Preliminary Version of the Third Catalogue of Nearby Stars, W. Gliese and H. Jahreiss, CDS ID V/70A. Accessed on line September 3, 2008.
- ^ From apparent magnitude and parallax.
- ^ HD 114378 -- Star in double system, database entry, SIMBAD, accessed on line September 3, 2008.
- ^ HD 114379 -- Star in double system, database entry, SIMBAD, accessed on line September 3, 2008.
- ^ (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.
- ^ (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.
- ^ (Chinese) English-Chinese Glossary of Chinese Star Regions, Asterisms and Star Name, Hong Kong Space Museum. Accessed on line November 23, 2010.
- ^ Richard Hinckley Allen: Star Names — Their Lore and Meaning: Coma Berenices
- ^ a b c d e BD+18 2697C -- Star in double system, database entry, SIMBAD. Accessed on line September 3, 2008.
- ^ a b c d 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
Star systems within 60–70 light-years from Earth with brightest member's absolute magnitude of +8.5 or brighter.Rho Puppis «Tureis» (62.7 ± 0.8 ly; 1 star)Theta Centauri «Menkent» (60.9 ± 0.9 ly; 1 star) • Aldebaran (65.1 ± 1.3 ly; 2 stars) • Epsilon Scorpii «Wei» (65.4 ± 1.1 ly; 1 star) • Alpha Arietis «Hamal» (65.9 ± 1.3 ly; 1 star, 1 planet: planet b)Beta Arietis «Sheratan» (59.6 ± 0.8 ly; 2 stars)‡ • Beta Pictoris (62.9 ± 0.6 ly; 1 star, 1 planet: planet b)Psi Velorum (59.7 ± 1.0 ly; 2 stars)‡ • Mu Virginis (60.9 ± 1.1 ly; 1 star)‡ • Alpha Chamaeleontis (63.5 ± 0.6 ly; 1 star) • Alpha Trianguli «Metallah» (64.1 ± 1.0 ly; 2 stars) • Eta Crucis (64.2 ± 0.6 ly; 2 stars) • Tau Cygni (66.4 ± 0.8 ly; 4 stars) • Theta Draconis (68.3 ± 0.8 ly; 2 stars) • Iota Virginis «Syrma» (69.8 ± 1.3 ly; 1 star)‡Chi Cancri (59.2 ± 1.0 ly; 1 star)‡ • Eta Corvi «Avis Satyra» (59.4 ± 0.7 ly; 1 star)‡ • Delta Equulei «Pherasauval» (60.0 ± 1.0 ly; 2 stars)‡ • Theta Cygni (60.7 ± 0.5 ly; 2 stars) • HR 1249 (62.7 ± 0.9 ly; 1 star) • 1 Centauri (62.8 ± 0.9 ly; 2 stars) • Omicron Aquilae (63.3 ± 0.9 ly; 3 stars) • c (45) Boötis (64.3 ± 1.0 ly; 2 stars) • Alpha Caeli (65.7 ± 0.7 ly; 2 stars) • Kappa Tucanae (66.04 ± 1.2 ly; 4 stars) • Gamma Doradus (66.2 ± 0.7 ly; 1 star) • Sigma² Ursae Majoris (66.7 ± 0.9 ly; 3 stars) • HR 1686 (68.4 ± 0.8 ly; 2 stars, 1 planet: planet b) • B Carinae (69.8 + 5.4/- 4.7 ly; 1 star)‡94 Aquarii (67.6 + 8.3/- 6.6 ly; 2 stars)‡ • Gliese 848.4 (69.4 ± 1.2 ly; 1 star, 1 planet: planet b)‡HD 217107 (64.3 ± 1.0 ly; 1 star, 2 planets: planet b • planet c) • 53 Aquarii (65.5 ± 3.5 ly; 2 stars) • GJ 3255 (67.4 ± 1.5 ly; 1 star, 1 planet: planet b) • 51 Arietis (69.0 ± 1.3 ly; 1 star)‡ • c (16) Cygni (69.8 ± 0.8 ly; 2 stars, 1 planet: planet Bb)‡Epsilon Reticuli (59.5 ± 0.5 ly; 1 star, 1 planet: planet b)‡ • Eta Serpentis «Tang» (61.8 ± 0.9 ly; 1 star) • Nu² Canis Majoris (64.7 ± 0.9 ly; 1 star, 1 planet: planet b)GJ 4130 (62.8 ± 1.1 ly; 2 stars, 1 planet: planet b) • Gliese 710 (63.0 ± 1.8 ly; 1 star) • HD 192263 (64.9 ± 1.5 ly; 1 star, 1 planet: planet b) • GJ 3769 (66.6 ± 1.5 ly; 1 star, 1 planet: planet b) • GJ 3651 (69.5 ± 1.5 ly; 1 star, 1 planet: planet b)‡ • GJ 4291 (70.2 ± 2.0 ly; 1 star, 1 planet: planet b)‡In left column are stellar classes of primary members of star systems. ‡Distance error margin extends out of declared distance interval. Italic are systems possibly located within declared distance interval, but probably not.Bayer - α (Diadem)
- β
- γ
Flamsteed - 1
- 2
- 3
- 4
- 5
- 6
- 7
- 8
- 9
- 10
- 11
- 12
- 13
- 14
- 15 (γ)
- 16
- 17
- 18
- 20
- 21
- 22
- 23
- 24
- 25
- 26
- 27
- 28
- 29
- 30
- 31
- 32
- 35
- 36
- 37
- 38
- 39
- 40
- 41
- 42 (α, Diadem)
- 43 (β)
Nearby - WISE 1217+1626
- β
Categories:- Bayer objects
- Binary stars
- Coma Berenices constellation
- F-type main sequence stars
- Stars with proper names
- Flamsteed objects
- Henry Draper Catalogue objects
- HIP objects
- Triple stars
- Durchmusterung objects
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