Location via proxy:   [ UP ]  
[Report a bug]   [Manage cookies]                
Jump to content

17 Comae Berenices

From Wikipedia, the free encyclopedia
(Redirected from 17 Com)
17 Comae Berenices
Location of 17 Com (circled)
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Coma Berenices
17 Com A
Right ascension 12h 28m 54.703s[1]
Declination +25° 54′ 46.27″[1]
Apparent magnitude (V) 5.242±0.004[2]
17 Com BC
Right ascension 12h 28m 44.565s[3]
Declination +25° 53′ 57.56″[3]
Apparent magnitude (V) 6.635[4]
Characteristics
17 Com A
Spectral type A0p[5]
A0 SrCrEu[2]
B−V color index −0.056±0.009[6]
Variable type α2 CVn + δ Sct(?)[7]
17 Com BC
Spectral type kA2hA9VmF0[8]
U−B color index 0.084[4]
B−V color index 0.216[4]
Astrometry
17 Com A
Radial velocity (Rv)−1.4±0.5[9] km/s
Proper motion (μ) RA: −23.539 mas/yr[1]
Dec.: −15.620 mas/yr[1]
Parallax (π)13.5382 ± 0.2245 mas[1]
Distance241 ± 4 ly
(74 ± 1 pc)
Absolute magnitude (MV)0.98[6]
17 Com BC
Radial velocity (Rv)−1.8±0.1[10] km/s
Proper motion (μ) RA: −22.296 mas/yr[3]
Dec.: −17.071 mas/yr[3]
Parallax (π)13.6383 ± 0.0913 mas[3]
Distance239 ± 2 ly
(73.3 ± 0.5 pc)
Absolute magnitude (MV)2.46[6]
Orbit[11]
Primary17 Com B
Companion17 Com C
Period (P)68.290±0.012 d
Eccentricity (e)0.296±0.008
Periastron epoch (T)2,448,313.4±0.4 JD
Argument of periastron (ω)
(secondary)		260.7±2.2°
Semi-amplitude (K1)
(primary)		14.0±0.2 km/s
Details
17 Com A
Mass2.38 M☉[2]
2.61 M☉[12]
2.75±0.3[13] M☉
Radius2.09[5] R☉
Luminosity42.7[5] L☉
Surface gravity (log g)4.27 cgs[12]
3.70±0.20[13] cgs
Temperature10,212 K[5]
9,309±250[13] K
Rotational velocity (v sin i)20.4±0.4[5] km/s
Age101[12] Myr
17 Com BC
Mass1.74±0.6[14] M☉
Surface gravity (log g)4.29±0.20[14] cgs
Temperature8,068±200[14] K
Rotational velocity (v sin i)22[4] km/s
Other designations
BU 1080, 17 Com, ADS 8568, WDS J12289+2555[15][16]
17 Com A: AI Com, BD+26°2354, GC 17012, HD 108662, HIP 60904, HR 4752, SAO 82330[15]
17 Com B: BD+26°2353, GC 17007, HD 108651, HIP 60891, HR 4751, SAO 82328[16]
Database references
17 Com A
SIMBADdata
17 Com B
SIMBADdata

17 Comae Berenices (17 Com) is a multiple star system in the northern constellation of Coma Berenices. The brighter component, 17 Com A, is a naked eye star with an apparent visual magnitude of 5.2.[2] It has a faint companion of magnitude 6.6,[6] 17 Com B, positioned at an angular separation of 146.4″ along a position angle of 251°, as of 2018.[17] They are located at a distance of approximately 240 light years from the Sun based on parallax measurements.[1]

The double nature of this system was documented by F. G. W. Struve in 1836.[17] The pair share a common proper motion through space[13] and thus may be associated. Component B is itself a binary star system, although only the brighter component is visible in the spectrum.[11] The Washington Double Star Catalogue lists the companion as component C, with a magnitude of 13.7 and a separation of 1.4″.[17] 17 Com has been recognized as members of the Coma Star Cluster,[18] but this is disputed.[19]

The star 17 Com A was classified as chemically peculiar by A. J. Cannon prior to 1918.[20] W. W. Morgan in 1932 found the star's spectral lines varied in strength and appearance,[21] and detected lines of the element europium.[22] H. W. Babcock and T. G. Cowling measured the Zeeman effect in this star, demonstrating in 1953 that it has a magnetic field.[23] In 1967, E. P. J. van den Heuvel noted the blue excess of this star, suggesting it is a blue straggler.[24] G. W. Preston and associates in 1969 found that the luminosity and magnetic field of this star varied in strength with a time scale of around five days.[25]

A light curve for AI Comae Berenices, plotted from TESS data[26]

17 Com A is a magnetic chemically peculiar Ap star with a stellar classification of A0p[5] or A0 SrCrEu,[2] with the latter indicating the spectrum shows abundance anomalies of the elements strontium, chromium, and europium. The level of silicon in the atmosphere is also enhanced[27] and it shows a significant helium deficiency.[5] It has the variable star designation of AI Com, and is classified as an Alpha2 Canum Venaticorum variable and a suspected Delta Scuti variable.[7] It has been identified as a suspected blue straggler.[13]

The primary has an estimated age of 101[12] million years and is spinning with a projected rotational velocity of 20 km/s.[5] It has more than double the mass and twice the radius of the Sun.[2][5] The magnetic field strength is 3,300±150 G.[5] It is radiating 43[5] times the luminosity of the Sun from its photosphere at an effective temperature of around 10,000 K.[5][13]

The co-moving companion, component B, is a single-lined spectroscopic binary with an orbital period of 68.3 days and an eccentricity (ovalness) of 0.3.[11] The visible member of this binary pair is a strong Am star[4] with a class of kA2hA9VmF0,[8] indicating it has the Calcium K-lines of an A0 star, the hydrogen lines of an A9 star, and the metallic lines of an F0 star.[28]

References

[edit]
  1. ^ a b c d e Brown, A. G. A.; et al. (Gaia collaboration) (2021). "Gaia Early Data Release 3: Summary of the contents and survey properties". Astronomy & Astrophysics. 649: A1. arXiv:2012.01533. Bibcode:2021A&A...649A...1G. doi:10.1051/0004-6361/202039657. S2CID 227254300. (Erratum: doi:10.1051/0004-6361/202039657e). Gaia EDR3 record for this source at VizieR.
  2. ^ a b c d e f Paunzen, E.; et al. (July 2021), "Magnetic chemically peculiar stars investigated by the Solar Mass Ejection Imager", Monthly Notices of the Royal Astronomical Society, 504 (3): 3758–3772, arXiv:2105.02206, Bibcode:2021MNRAS.504.3758P, doi:10.1093/mnras/stab1100.
  3. ^ a b c d Brown, A. G. A.; et al. (Gaia collaboration) (2021). "Gaia Early Data Release 3: Summary of the contents and survey properties". Astronomy & Astrophysics. 649: A1. arXiv:2012.01533. Bibcode:2021A&A...649A...1G. doi:10.1051/0004-6361/202039657. S2CID 227254300. (Erratum: doi:10.1051/0004-6361/202039657e). Gaia EDR3 record for this source at VizieR.
  4. ^ a b c d e Iliev, I. Kh.; et al. (August 2006), "Abundance analysis of Am binaries and search for tidally driven abundance anomalies - II. HD861, HD18778, HD20320, HD29479, HD96528 and HD108651", Monthly Notices of the Royal Astronomical Society, 370 (2): 819–827, Bibcode:2006MNRAS.370..819I, doi:10.1111/j.1365-2966.2006.10513.x, S2CID 56133360.
  5. ^ a b c d e f g h i j k l Romanovskaya, A. M.; et al. (September 2020), "Fundamental parameters of Ap-star HD 108662", INASAN Science Reports, 5 (4): 219–223, arXiv:2006.15950, Bibcode:2020INASR...5..219R, doi:10.26087/INASAN.2020.5.4.010, S2CID 220250089.
  6. ^ a b c d 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.
  7. ^ a b Samus, N. N.; et al. (2017), "General Catalogue of Variable Stars", Astronomy Reports, 5.1, 61 (1): 80–88, Bibcode:2017ARep...61...80S, doi:10.1134/S1063772917010085, S2CID 125853869.
  8. ^ a b Abt, H. A.; Cardona, O. (1984), "The nature of the visual companions of AP and AM stars", The Astrophysical Journal, 276: 266, Bibcode:1984ApJ...276..266A, doi:10.1086/161610.
  9. ^ Gontcharov, G. A. (November 2006), "Pulkovo Compilation of Radial Velocities for 35495 Hipparcos stars in a common system", Astronomy Letters, 32 (11): 759–771, arXiv:1606.08053, Bibcode:2006AstL...32..759G, doi:10.1134/S1063773706110065, S2CID 119231169.
  10. ^ 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.
  11. ^ a b c Abt, Helmut A.; Willmarth, Daryl W. (August 1999), "Binaries in the Praesepe and Coma Star Clusters and Their Implications for Binary Evolution", The Astrophysical Journal, 521 (2): 682–690, Bibcode:1999ApJ...521..682A, doi:10.1086/307569, S2CID 119772785.
  12. ^ a b c d 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.
  13. ^ a b c d e f Monier, Richard; Deal, Morgan (July 2020), "The Evolutionary Status of 17 Com, The Hottest Member of Coma Berenices", Research Notes of the AAS, 4 (7): 104, Bibcode:2020RNAAS...4..104M, doi:10.3847/2515-5172/aba35a, S2CID 225795832, 104.
  14. ^ a b c Deal, Morgan; Monier, Richard (August 2020), "The Surface Abundances of 17 Com B: A Test for Self-consistent Evolutionary Models", Research Notes of the AAS, 4 (8): 144, Bibcode:2020RNAAS...4..144D, doi:10.3847/2515-5172/abb01f, S2CID 225379385, 144.
  15. ^ a b "HD 108662". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2022-01-14.
  16. ^ a b "HD 108651". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2022-01-14.
  17. ^ a b c Mason, B. D.; et al. (2014), "The Washington Visual Double Star Catalog", The Astronomical Journal, 122 (6): 3466–3471, Bibcode:2001AJ....122.3466M, doi:10.1086/323920.
  18. ^ Casewell, S. L.; et al. (January 2006), "New stellar members of the Coma Berenices open star cluster", Monthly Notices of the Royal Astronomical Society, 365 (2): 447–453, arXiv:astro-ph/0510133, Bibcode:2006MNRAS.365..447C, doi:10.1111/j.1365-2966.2005.09689.x, S2CID 17595520.
  19. ^ Silaj, J.; Landstreet, J. D. (June 2014), "Accurate age determinations of several nearby open clusters containing magnetic Ap stars", Astronomy & Astrophysics, 566: 18, arXiv:1407.4531, Bibcode:2014A&A...566A.132S, doi:10.1051/0004-6361/201321468, S2CID 53370832, A132.
  20. ^ Perrine, C. D. (June 1918), "On the cause underlying the spectral differences of the stars", Astrophysical Journal, 47: 289–323, Bibcode:1918ApJ....47..289P, doi:10.1086/142406.
  21. ^ Morgan, W. W. (September 1932), "A Study of the Composite Spectrum of the A-Type Star 14 Comae", Astrophysical Journal, 76: 144, Bibcode:1932ApJ....76..144M, doi:10.1086/143410.
  22. ^ Morgan, W. W. (January 1932), "Studies in Peculiar Stellar Spectra. III. on the Occurrence of Europium in A-Type Stars", Astrophysical Journal, 75: 46, Bibcode:1932ApJ....75...46M, doi:10.1086/143354.
  23. ^ Babcock, H. W.; Cowling, T. G. (1953), "General magnetic fields in the Sun and stars (Report on progress of astronomy)", Monthly Notices of the Royal Astronomical Society, 113: 357–381, Bibcode:1953MNRAS.113..357B, doi:10.1093/mnras/113.3.357.
  24. ^ van den Heuvel, E. P. J. (April 1967), "The origin of blue stragglers and peculiar and metallic-line stars", The Observatory, 87: 68–72, Bibcode:1967Obs....87...68V.
  25. ^ Preston, G. W.; et al. (May 1969), "The magnetic field and light variations of 17 COM and kap Cnc", Astrophysical Journal, 156: 653, Bibcode:1969ApJ...156..653P, doi:10.1086/149995.
  26. ^ "MAST: Barbara A. Mikulski Archive for Space Telescopes". Space Telescope Science Institute. Retrieved 8 December 2021.
  27. ^ Savanov, I. S.; et al. (November 1996), "A study of the atmospheres of the SrCrEu stars 17 Com A and 21 Com in the Coma Cluster", Astronomy Letters, 22 (6): 815–821, Bibcode:1996AstL...22..815S.
  28. ^ Gray, Richard O.; Corbally, J. (2009), Stellar Spectral Classification, Princeton University Press, pp. 176–183, ISBN 978-0691125114
[edit]
Retrieved from "https://en.wikipedia.org/w/index.php?title=17_Comae_Berenices&oldid=1241714255"