12 Comae Berenices

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12 Comae Berenices
12 Comae Berenices.jpg
12 Comae Berenices in optical light
Observation data
Epoch J2000.0       Equinox J2000.0
Constellation Coma Berenices
Right ascension 12h 22m 30.31076s [1]
Declination +25° 50′ 46.1896″ [1]
Apparent magnitude  (V)4.80 [2]
Characteristics
Spectral type F6 III + A3 V [3]
U−B color index 0.47/0.09 [2]
B−V color index 0.82/0.11 [2]
Astrometry
Radial velocity (Rv)+0.5±0.9 [4]  km/s
Proper motion (μ)RA: −10.847 [1]   mas/yr
Dec.: −9.546 [1]   mas/yr
Parallax (π)11.8280 ± 0.2353 [1]   mas
Distance 276 ± 5  ly
(85 ± 2  pc)
Absolute magnitude  (MV)0.55±0.06 / 1.05±0.06 [2]
Orbit [5] [6]
Period (P)396.54±0.12 d
Eccentricity (e)0.566±0.050
Inclination (i)66±2 [2] °
Periastron epoch (T)2444502.4±8.0  JD
Argument of periastron (ω)
(secondary)		95.5±3.5°
Semi-amplitude (K1)
(primary)		22.42±2.22 km/s
Details [2]
12 Com A
Mass 2.6±0.2  M☉
Radius 8.9±0.8  R☉
Luminosity 56.2+2.7
−2.5  L☉
Temperature 5,300±200  K
Age 670  Myr
12 Com B
Mass 2.05±0.2  M☉
Radius 2.5±0.3  R☉
Luminosity30.2+2.2
−2.2  L☉
Temperature 8,500±500  K
Other designations
12 Com, NSV  5581, BD+26°2337, FK5  1318, HD  107700, HIP  60351, HR  4707, SAO  82273, WDS J12225+2551A [7]
Database references
SIMBAD data

12 Comae Berenices is a binary star system in the northern constellation of Coma Berenices. It is the brightest member of the Coma Cluster and is visible to the naked eye with an apparent visual magnitude of 4.80. [2] Although listed as a suspected variable star, there is no photometric evidence of it being variable in luminosity. However, the radial velocity was found to be variable, as announced by W. W. Campbell in 1910. The first orbital solution was published by Vinter Hansen in the 1940s. [2] It is a double-lined spectroscopic binary with an orbital period of 396.5 days and an eccentricity of 0.566. [6]

This system consists of two stars, an evolved F-type giant star and a smaller but higher temperature A-type main-sequence star. [3] Griffin and Griffin (2011) suggested that the secondary component may have begun its evolution away from the main sequence, and instead assigned it a luminosity class of IV. The primary, designated component A, has 2.6 times the mass of the Sun and has expanded to 8.9 times the Sun's radius. It is radiating 56 times the Sun's luminosity from its enlarged photosphere at an effective temperature of 5,300 K. Its companion, component B, has double the Sun's mass and 2.5 times the radius. It shines with 30 times the luminosity of the Sun at 8,500 K. [2]

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Omicron Tauri

ο Tauri, Latinized as Omicron Tauri, is a binary star system in the constellation Taurus, near the constellation border with Cetus. It has a yellow hue and is visible to the naked eye with an apparent visual magnitude of 3.61. It is approximately 191 light years from the Sun based on parallax, but is drifting closer with a radial velocity of −20 km/s. This system has the Flamsteed designation 1 Tauri; Omicron Tauri is the Bayer designation.

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31 Vulpeculae

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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.

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23 Comae Berenices is a binary star system in the northern constellation of Coma Berenices, situated a few degrees away from the North Galactic Pole. It is visible to the naked eye as a faint, white-hued point of light with an apparent visual magnitude of 4.80. The system is located around 310 light years away from the Sun, based on parallax. It is moving closer to the Earth with a heliocentric radial velocity of −16 km/s.

35 Comae Berenices is a multiple star system in the northern constellation of Coma Berenices, located about 6° from the north galactic pole. It is faintly visible to the naked eye with an apparent visual magnitude of 4.93. Based upon parallax measurements, it is located around 280 light years from the Sun. The system is moving closer to the Earth with a heliocentric radial velocity of −6 km/s.

16 Comae Berenices is a single star in the northern constellation of Coma Berenices. 16 Comae Berenices is the Flamsteed designation. It is a member of the Coma Star Cluster and is visible to the naked eye with an apparent visual magnitude of 4.96. Based upon an annual parallax shift of 11.7 mas, it is located about 279 light years away.

HD 106760 is a single-lined spectroscopic binary star system in the northern constellation of Coma Berenices. It is faintly visible to the naked eye, having an apparent visual magnitude of 4.99. The system is located around 38 light years away, as determined from its annual parallax shift of 10.2417 mas. It is moving closer with a heliocentric radial velocity of −40 km/s, and is expected to come as close as 259 ly in about 772,000 years.

Tau8 Eridani, Latinized from τ8 Eridani, is a binary star system in the constellation Eridanus. It is visible to the naked eye with a combined apparent visual magnitude of 4.65. The distance to this system can be estimated via the parallax method, yielding a value of around 380 light years.

Pi<sup>5</sup> Orionis Star in the constellation Orion

Pi5 Orionis (π5 Ori, π5 Orionis) is a binary star system in the constellation Orion. It has an apparent visual magnitude of 3.69, which is bright enough to be visible to the naked eye on a clear night. Based upon an annual parallax shift of 2.43 mas, it is around 1,300 light years distant from the Sun.

HD 21278 Star in the constellation Perseus

HD 21278 is a binary star system in the constellation Perseus, located within the 60±7 million year old Alpha Persei Cluster. It has a blue-white hue and is visible to the naked eye with a combined apparent visual magnitude of 4.99. The system is located at a distance of approximately 580 light years from the Sun based on parallax, and it is drifting further away with a radial velocity of +1.20 km/s.

Chi2 Hydrae, Latinised from χ2 Hydrae, is a binary star system in the equatorial constellation of Hydra. Based upon an annual parallax shift of 4.6 mas as seen from Earth, it is located roughly 710 light years from the Sun. It is visible to the naked eye with a combined apparent visual magnitude of 5.71.

16 Lacertae is a triple star system in the northern constellation of Lacerta, located about 1,580 light years from the Sun. It has the variable star designation EN Lacertae; 16 Lacertae is the Flamsteed designation. This system is visible to the naked eye as a faint blue-white hued star with a maximum apparent visual magnitude of +5.587. It is moving closer to the Earth with a heliocentric radial velocity of −12 km/s.

19 Lyncis is a triple star system in the northern constellation of Lynx. A telescope reveals it consists of two blue-white hued stars of magnitudes 5.80 and 6.86 that are 14.750 arcseconds apart, with a visual companion of magnitude 7.6 that is 3.5 arcminutes distant. The first two are located around 680–690 light years away from the Sun, based on parallax measurements. Their radial velocity measurements are poorly constrained, but suggest the system is trending away from the Earth.

HD 163840 is a binary star system in the northern constellation of Hercules. It has a combined apparent visual magnitude of 6.45, which falls just below the brightness level that is visible to the naked eye for people with normal eyesight. An annual parallax shift of 35.40 mas provides a distance estimate of about 92 light years. The system is moving closer to the Sun with a radial velocity of −33 km/s. In about 769,000 years, it will make perihelion at a separation of around 27.2 ly (8.33 pc).

24 Comae Berenices Star in the constellation Coma Berenices

24 Comae Berenices is a triple star system in the northern constellation of Coma Berenices. It is visible to the naked eye, with the brightest component being an orange-hued star with an apparent visual magnitude of 5.03. The system is located at a distance of approximately 269 light years from the Sun based on parallax, and is drifting further away with radial velocities of 3–5 km/s.

21 Comae Berenices is a variable star in the northern constellation of Coma Berenices. It has the variable star designation UU Comae Berenices, while 21 Comae Berenices is the Flamsteed designation. According to R. H. Allen, English orientalist Thomas Hyde attributed the ancient title Kissīn to this star, a name that comes from a climbing plant – either bindweed or dog rose. This star has a white hue and is just visible to the naked eye with an apparent visual magnitude that fluctuates around 5.47. Based upon parallax measurements, it is located at a distance of approximately 272 light years away from the Sun. It is a single star but is a confirmed physical member of the Melotte 111 open cluster.

References

  1. 1 2 3 4 5 Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics . 616. A1. arXiv: 1804.09365 . Bibcode: 2018A&A...616A...1G . doi: 10.1051/0004-6361/201833051 . Gaia DR2 record for this source at VizieR.
  2. 1 2 3 4 5 6 7 8 9 Griffin, R. E. M.; Griffin, R. F. (February 2011), "Composite spectra: XVII. 12 Comae, a member of the Coma open cluster", Astronomische Nachrichten, 332 (2): 105–115, Bibcode:2011AN....332..105G, doi: 10.1002/asna.201011514
  3. 1 2 Abt, Helmut A. (2008). "Visual Multiples. IX. MK Spectral Types". The Astrophysical Journal Supplement Series. 176 (1): 216–217. Bibcode:2008ApJS..176..216A. doi: 10.1086/525529 .
  4. ↑ Evans, D. S. (June 20–24, 1966). "The Revision of the General Catalogue of Radial Velocities". In Batten, Alan Henry; Heard, John Frederick (eds.). Determination of Radial Velocities and their Applications, Proceedings from IAU Symposium no. 30. 30. University of Toronto: International Astronomical Union. p. 57. Bibcode:1967IAUS...30...57E.
  5. ↑ Pourbaix, D.; et al. (2004). "SB9: The ninth catalogue of spectroscopic binary orbits". Astronomy and Astrophysics. 424 (2): 727–732. arXiv: astro-ph/0406573 . Bibcode:2004A&A...424..727P. doi:10.1051/0004-6361:20041213. S2CID   119387088.
  6. 1 2 Mermilliod, J. -C; et al. (2007). "Red giants in open clusters. XIII. Orbital elements of 156 spectroscopic binaries". Astronomy and Astrophysics. 473 (3): 829. Bibcode:2007A&A...473..829M. doi: 10.1051/0004-6361:20078007 .
  7. ↑ "12 Com". SIMBAD . Centre de données astronomiques de Strasbourg . Retrieved December 30, 2018.
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