23 Comae Berenices
23 Comae Berenices is a binary star[7] system in the northern constellation of Coma Berenices, situated a few degrees away from the North Galactic Pole.[11] It is visible to the naked eye as a faint, white-hued point of light with an apparent visual magnitude of 4.80.[2] The system is located around 310 light years away from the Sun, based on parallax.[1] It is moving closer to the Earth with a heliocentric radial velocity of −16 km/s.[6]
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Coma Berenices |
| Right ascension | 12h 34m 51.08058s[1] |
| Declination | +22° 37′ 45.3303″[1] |
| Apparent magnitude (V) | 4.80[2] (4.96 + 6.90)[3] |
| Characteristics | |
| Spectral type | A0IV[4] |
| U−B color index | −0.01[5] |
| B−V color index | +0.012±0.015[2] |
| Astrometry | |
| Radial velocity (Rv) | −16.0±1.8[6] km/s |
| Proper motion (μ) | RA: −58.89[1] mas/yr Dec.: 28.31[1] mas/yr |
| Parallax (π) | 10.52 ± 0.52 mas[1] |
| Distance | 310 ± 20 ly (95 ± 5 pc) |
| Absolute magnitude (MV) | −0.08[2] |
| Orbit[7] | |
| Period (P) | 33.04 yr |
| Semi-major axis (a) | 0.219″ |
| Eccentricity (e) | 0.898 |
| Inclination (i) | 109.7° |
| Longitude of the node (Ω) | 24.3° |
| Periastron epoch (T) | B1964.62 |
| Argument of periastron (ω) (secondary) | 214.5° |
| Details | |
| Mass | 2.15[8] M☉ |
| Radius | 3.0[9] R☉ |
| Luminosity | 104.00[2] L☉ |
| Surface gravity (log g) | 3.85[8] cgs |
| Temperature | 9,675±329[8] K |
| Rotational velocity (v sin i) | 40[8] km/s |
| Age | 210[8] Myr |
| Other designations | |
| Database references | |
| SIMBAD | data |
The components of this system orbit each other with a period of 33 years, a large eccentricity of 0.9, and an angular semimajor axis of 0.219″.[7] The primary, designated component A, is a magnitude 4.96[3] star with a stellar classification of A0IV,[4] matching an A-type subgiant that has exhausted the supply of hydrogen at its core and is in the process of evolving into a giant. Bychkov et al. (2009) list it as an Am star with an average field strength of 26×10−4 T.[12]
The primary is 210[8] million years old and is spinning with a projected rotational velocity of 40 km/s.[8] It has 2.15[8] times the mass of the Sun and about three[9] times the Sun's radius. The star is radiating 104[2] times the luminosity of the Sun from its photosphere at an effective temperature of 9,675 K.[8]
References Edit
- ^ a b c d e f van Leeuwen, F. (2007). "Validation of the new Hipparcos reduction". Astronomy and Astrophysics. 474 (2): 653–664. arXiv:0708.1752. Bibcode:2007A&A...474..653V. doi:10.1051/0004-6361:20078357. S2CID 18759600.
- ^ a b c d e f Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters, 38 (5): 331, arXiv:1108.4971, Bibcode:2012AstL...38..331A, doi:10.1134/S1063773712050015, S2CID 119257644.
- ^ a b Malkov, O. Yu.; Tamazian, V. S.; Docobo, J. A.; Chulkov, D. A. (2012). "Dynamical Masses of a Selected Sample of Orbital Binaries". Astronomy and Astrophysics. 546: 5. Bibcode:2012A&A...546A..69M. doi:10.1051/0004-6361/201219774. A69.
- ^ a b Cowley, A.; Cowley, C.; Jaschek, M.; Jaschek, C. (April 1969). "A study of the bright A stars. I. A catalogue of spectral classifications". Astronomical Journal. 74: 375–406. Bibcode:1969AJ.....74..375C. doi:10.1086/110819.
- ^ Mermilliod, J.-C. (1986). "Compilation of Eggen's UBV data, transformed to UBV (unpublished)". Catalogue of Eggen's UBV Data. Bibcode:1986EgUBV........0M.
- ^ a b de Bruijne, J. H. J.; Eilers, A.-C. (October 2012), "Radial velocities for the HIPPARCOS-Gaia Hundred-Thousand-Proper-Motion project", Astronomy & Astrophysics, 546: 14, arXiv:1208.3048, Bibcode:2012A&A...546A..61D, doi:10.1051/0004-6361/201219219, S2CID 59451347, A61.
- ^ a b c Seymour, Diana M.; Mason, Brian D.; Hartkopf, William I.; Wycoff, Gary L. (February 2002), "Binary Star Orbits. II. Preliminary First Orbits for 117 Systems", The Astronomical Journal, 123 (2): 1023–1038, Bibcode:2002AJ....123.1023S, doi:10.1086/338441, S2CID 122326479.
- ^ a b c d e f g h i David, Trevor J.; Hillenbrand, Lynne A. (2015). "The Ages of Early-Type Stars: Strömgren Photometric Methods Calibrated, Validated, Tested, and Applied to Hosts and Prospective Hosts of Directly Imaged Exoplanets". The Astrophysical Journal. 804 (2): 146. arXiv:1501.03154. Bibcode:2015ApJ...804..146D. doi:10.1088/0004-637X/804/2/146. S2CID 33401607.
- ^ a b Pasinetti Fracassini, L. E.; et al. (February 2001). "Catalogue of Apparent Diameters and Absolute Radii of Stars (CADARS)". Astronomy and Astrophysics (Third ed.). 367 (2): 521–524. arXiv:astro-ph/0012289. Bibcode:2001A&A...367..521P. doi:10.1051/0004-6361:20000451. S2CID 425754.
- ^ "23 Com". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 8 September 2012.
- ^ Straizys, V.; Meistas, E. (1989). "Photoelectric photometry of bright stars in the vicinity of the North Galactic Pole". Vilnius Astronomijos Observatorijos Biuletenis. 84: 26. Bibcode:1989VilOB..84...26S.
- ^ Bychkov, V. D.; et al. (2009), "Catalogue of averaged stellar effective magnetic fields - II. Re-discussion of chemically peculiar A and B stars", Monthly Notices of the Royal Astronomical Society, 394 (3): 1338, Bibcode:2009MNRAS.394.1338B, doi:10.1111/j.1365-2966.2008.14227.x, S2CID 120268049.