Astronomy:24 Comae Berenices
240px Map showing location of 24 Comae Berenices | |
| Observation data {{#ifeq:J2000.0|J2000.0 (ICRS)|Epoch J2000.0 Equinox J2000.0 (ICRS)| Epoch J2000.0 [[Astronomy:Equinox (celestial coordinates)|Equinox J2000.0}} | |
|---|---|
| Constellation | Coma Berenices |
| A | |
| Right ascension | 12h 35m 07.76130s[1] |
| Declination | +18° 22′ 37.4133″[1] |
| Apparent magnitude (V) | 5.03[2] |
| B | |
| Right ascension | 12h 35m 06.34558s[1] |
| Declination | +18° 22′ 37.5320″[1] |
| Apparent magnitude (V) | 6.57[2] |
| Characteristics | |
| A | |
| Spectral type | K0II-III[3] |
| B−V color index | 1.152±0.018[2] |
| B | |
| Evolutionary stage | A9V[3] |
| B−V color index | 0.265±0.015[2] |
| Astrometry | |
| A | |
| Radial velocity (Rv) | +3.03±0.10[2] km/s |
| Proper motion (μ) | RA: −3.719[1] mas/yr Dec.: +23.106[1] mas/yr |
| Parallax (π) | 8.5745 ± 0.1996[1] mas |
| Distance | 380 ± 9 ly (117 ± 3 pc) |
| Absolute magnitude (MV) | 0.30[4] |
| B | |
| Radial velocity (Rv) | +4.90±0.50[2] km/s |
| Proper motion (μ) | RA: −2.320[1] mas/yr Dec.: +21.236[1] mas/yr |
| Parallax (π) | 8.8346 ± 0.0695[1] mas |
| Distance | 369 ± 3 ly (113.2 ± 0.9 pc) |
| Orbit[5] | |
| Primary | Ba |
| Companion | Bb |
| Period (P) | 7.336673±0.000087 d |
| Semi-major axis (a) | 1.007±0.037 mas |
| Eccentricity (e) | 0.2585±0.0012 |
| Inclination (i) | 61.40±3.89° |
| Longitude of the node (Ω) | 136.17±2.86° |
| Periastron epoch (T) | 2,459,361.967±0.011 JD |
| Argument of periapsis (ω) (primary) | 302.33±0.28° |
| Semi-amplitude (K1) (primary) | 68.16±0.09 km/s |
| Semi-amplitude (K2) (secondary) | 81.28±0.20 km/s |
| Details | |
| A | |
| Mass | 4.40[6] M☉ |
| Radius | 19.95+0.69 −2.58[1] R☉ |
| Luminosity | 173.3±4.6[1] L☉ |
| Surface gravity (log g) | 2.50[4] cgs |
| Temperature | 4,688+337 −79[1] K |
| Metallicity [Fe/H] | −0.09[7] dex |
| Ba | |
| Mass | 1.838±0.218[5] M☉ |
| Radius | 2.28±0.06[5] R☉ |
| Luminosity | 15.6±1.3[5] L☉ |
| Surface gravity (log g) | 3.86±0.01[5] cgs |
| Temperature | 7,630±120[5] K |
| Metallicity [Fe/H] | 0.54[8] dex |
| Rotational velocity (v sin i) | 14.5±1.5 km/s |
| Bb | |
| Mass | 1.541±0.184[5] M☉ |
| Radius | 1.70±0.07[5] R☉ |
| Luminosity | 7.2±0.9[5] L☉ |
| Surface gravity (log g) | 4.09±0.02[5] cgs |
| Temperature | 7,180±140[5] K |
| Rotational velocity (v sin i) | 14.2±1.1[5] km/s |
| Other designations | |
| A: NSV 5748, GC 17147, HD 109511, HIP 61418, HR 4792, SAO 100160[9] | |
| B: GC 17146, HD 109510, HIP 61415, HR 4791, SAO 100159[10] | |
| Database references | |
| SIMBAD | A |
| B | |
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.[2] 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.[2]
This system can be resolved in a telescope as a pair of stars with an angular separation of 20.2″ along a position angle of 272°, as of 2018.[11] They share a common motion through space and thus appear to be physically associated,[12] with a wide projected separation of 1,400 astronomical unit|AU or greater.[13] If they are bound in an orbit, the estimated period is approximately 28,000 years.[6]
The brighter member of this system is an aging giant or bright giant star with a stellar classification of K0II-III.[3] It has exhausted the supply of hydrogen at its core and expanded to 20[1] times the girth of the Sun. This is a suspected variable that has been recorded ranging in brightness from magnitude 4.98 down to 5.06.[14] The star is radiating 173[1] times the luminosity of the Sun from its swollen photosphere at an effective temperature of 4,688 K.[1]
The fainter component at magnitude 6.57[2] is a double-lined spectroscopic binary with an orbital period of 7.33 days and an eccentricity of 0.26.[12] The primary member of this pair is an A-type main-sequence star with a stellar classification of A9V.[3] It is a metallic-lined Am star[15] with 2.2 times the radius of the Sun.[5] The stars radiate about 16 and 7 times the Sun's luminosity from its photosphere, respectively, at effective temperatures of 7,630 and 7180 K, respectively.[5] Both have relatively low projected rotational velocity of around 14 km/s,[5] and it is suspected the rotations of this binary system may be synchronized.[8] The system is a source for X-ray emission, which is most likely coming from the secondary.[16]
References
- ↑ 1.00 1.01 1.02 1.03 1.04 1.05 1.06 1.07 1.08 1.09 1.10 1.11 1.12 1.13 1.14 1.15 Brown, A. G. A. (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics 616: A1. doi:10.1051/0004-6361/201833051. Bibcode: 2018A&A...616A...1G.
- ↑ 2.0 2.1 2.2 2.3 2.4 2.5 2.6 2.7 2.8 Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters 38 (5): 331, doi:10.1134/S1063773712050015, Bibcode: 2012AstL...38..331A.
- ↑ 3.0 3.1 3.2 3.3 Yoss, K. M.; Griffin, R. F. (September 1997), "Radial Velocities and DDO, BV Photometry of Henry Draper G5-M Stars Near the North Galactic Pole", Journal of Astrophysics and Astronomy 18 (2–3): 161, doi:10.1007/BF02714877, Bibcode: 1997JApA...18..161Y.
- ↑ 4.0 4.1 McWilliam, Andrew (1990), "High-Resolution Spectroscopic Survey of 671 GK Giants. I. Stellar Atmosphere Parameters and Abundances", The Astrophysical Journal Supplement Series 74: 1075, doi:10.1086/191527, Bibcode: 1990ApJS...74.1075M.
- ↑ 5.00 5.01 5.02 5.03 5.04 5.05 5.06 5.07 5.08 5.09 5.10 5.11 5.12 5.13 5.14 Lester, Kathryn V. et al. (2022), "Visual Orbits of Spectroscopic Binaries with the CHARA Array. IV. HD 61859, HD 89822, HD 109510, and HD 191692", The Astronomical Journal 164 (6): 228, doi:10.3847/1538-3881/ac9385, Bibcode: 2022AJ....164..228L.
- ↑ 6.0 6.1 Tokovinin, A. (September 2008), "Comparative statistics and origin of triple and quadruple stars", Monthly Notices of the Royal Astronomical Society 389 (2): 925–938, doi:10.1111/j.1365-2966.2008.13613.x, Bibcode: 2008MNRAS.389..925T.
- ↑ Malagnini, M. L. et al. (2000), "Observations and Atmospheric Parameters of Super-Metal-rich Candidates", The Publications of the Astronomical Society of the Pacific 112 (777): 1455, doi:10.1086/317714, Bibcode: 2000PASP..112.1455M.
- ↑ 8.0 8.1 Stickland, D. J. (1973), "On the atmospheric abundances of seven Am SB2 systems", Monthly Notices of the Royal Astronomical Society 161 (2): 193, doi:10.1093/mnras/161.2.193, Bibcode: 1973MNRAS.161..193S.
- ↑ "24 Com A". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=24+Com+A.
- ↑ "24 Com B". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=24+Com+B.
- ↑ Mason, B. D. et al. (2014), "The Washington Visual Double Star Catalog", The Astronomical Journal 122 (6): 3466, doi:10.1086/323920, Bibcode: 2001AJ....122.3466M, http://vizier.u-strasbg.fr/viz-bin/VizieR?-source=B/wds, retrieved 2015-07-22.
- ↑ 12.0 12.1 Mayor, M.; Mazeh, T. (January 1987), "The frequency of triple and multiple stellar systems", Astronomy and Astrophysics 171: 157−177, Bibcode: 1987A&A...171..157M.
- ↑ Abt, Helmut A. (August 1988), "Maximum Separations among Cataloged Binaries", Astrophysical Journal 331: 922, doi:10.1086/166609, Bibcode: 1988ApJ...331..922A.
- ↑ Samus', N. N et al. (2017), "General catalogue of variable stars: Version GCVS 5.1", Astronomy Reports 61 (1): 80, doi:10.1134/S1063772917010085, Bibcode: 2017ARep...61...80S.
- ↑ Chen, P. S. et al. (2017), "A New Photometric Study of Ap and Am Stars in the Infrared", The Astronomical Journal 153 (5): 218, doi:10.3847/1538-3881/aa679a, Bibcode: 2017AJ....153..218C.
- ↑ Schröder, C.; Schmitt, J. H. M. M. (November 2007), "X-ray emission from A-type stars", Astronomy and Astrophysics 475 (2): 677–684, doi:10.1051/0004-6361:20077429, Bibcode: 2007A&A...475..677S.
 |  |
