Astronomy:24 Comae Berenices: Difference between revisions

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Short description: Star in the constellation Coma Berenices
24 Comae Berenices
Melotte111 karte.png
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
Distance380 ± 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
Distance369 ± 3 ly
(113.2 ± 0.9 pc)
Orbit[5]
PrimaryBa
CompanionBb
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
Mass4.40[6] M
Radius19.95+0.69
−2.58
[1] R
Luminosity173.3±4.6[1] L
Surface gravity (log g)2.50[4] cgs
Temperature4,688+337
−79
[1] K
Metallicity [Fe/H]−0.09[7] dex
B
Mass1.838/1.541[5] M
Radius2.28/1.70[5] R
Luminosity15.6/7.2[5] L
Surface gravity (log g)3.86/4.09[5] cgs
Temperature7630/7180[5] K
Rotational velocity (v sin i)14.5/14.2[5] km/s
Other designations
A: NSV 5748, GC 17147, HD 109511, HIP 61418, HR 4792, SAO 100160[8]
B: GC 17146, HD 109510, HIP 61415, HR 4791, SAO 100159[9]
Database references
SIMBADA
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.[10] They share a common motion through space and thus appear to be physically associated,[11] with a wide projected separation of 1,400 astronomical unit|AU or greater.[12] 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.[13] 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.[11] 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[14] 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.[15] The system is a source for X-ray emission, which is most likely coming from the secondary.[16]

References

  1. 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. Bibcode2018A&A...616A...1G. 
  2. 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, Bibcode2012AstL...38..331A. 
  3. 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, Bibcode1997JApA...18..161Y. 
  4. 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, Bibcode1990ApJS...74.1075M. 
  5. 5.0 5.1 5.2 5.3 5.4 5.5 5.6 5.7 5.8 5.9 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, Bibcode2022AJ....164..228L. 
  6. 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, Bibcode2008MNRAS.389..925T. 
  7. 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, Bibcode2000PASP..112.1455M. 
  8. "24 Com A". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=24+Com+A. 
  9. "24 Com B". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=24+Com+B. 
  10. Mason, B. D. et al. (2014), "The Washington Visual Double Star Catalog", The Astronomical Journal 122 (6): 3466, doi:10.1086/323920, Bibcode2001AJ....122.3466M, http://vizier.u-strasbg.fr/viz-bin/VizieR?-source=B/wds, retrieved 2015-07-22. 
  11. 11.0 11.1 Mayor, M.; Mazeh, T. (January 1987), "The frequency of triple and multiple stellar systems", Astronomy and Astrophysics 171: 157−177, Bibcode1987A&A...171..157M. 
  12. Abt, Helmut A. (August 1988), "Maximum Separations among Cataloged Binaries", Astrophysical Journal 331: 922, doi:10.1086/166609, Bibcode1988ApJ...331..922A. 
  13. Samus', N. N et al. (2017), "General catalogue of variable stars: Version GCVS 5.1", Astronomy Reports 61 (1): 80, doi:10.1134/S1063772917010085, Bibcode2017ARep...61...80S. 
  14. 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, Bibcode2017AJ....153..218C. 
  15. 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, Bibcode1973MNRAS.161..193S. 
  16. 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, Bibcode2007A&A...475..677S.