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16 Lyrae

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16 Lyrae
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Lyra
Right ascension 19h 01m 26.38262s[1]
Declination +46° 56′ 05.1475″[1]
Apparent magnitude (V) 5.00[2]
Characteristics
Evolutionary stage main sequence[3]
Spectral type A6 IV[4] or A7 V[5]
B−V color index +0.186±0.005[2]
Astrometry
Radial velocity (Rv)+4.36±0.21[1] km/s
Proper motion (μ) RA: +22.004 mas/yr[1]
Dec.: −80.894 mas/yr[1]
Parallax (π)25.7832 ± 0.0688 mas[1]
Distance126.5 ± 0.3 ly
(38.8 ± 0.1 pc)
Absolute magnitude (MV)+2.13[2]
Details[6]
Mass1.722±0.013 M
Radius1.644+0.025
−0.023
(equatorial)
1.622+0.023
−0.022
(polar) R
Luminosity10.45+0.30
−0.28
 L
Surface gravity (log g)4.28[7] cgs
Temperature8,028 (equator)
8,242 (polar) K
Rotational velocity (v sin i)85.1+16.3
−31.6
 km/s
Age401+31
−32
 Myr
Other designations
16 Lyr, NSV 11677, BD+46°2602, HD 177196, HIP 93408, HR 7215, SAO 48011, WDS J19014+4656A, GSC 03545-03041[8]
Database references
SIMBADdata

16 Lyrae is a suspected astrometric binary[9] star system in the constellation Lyra,[8] located 126 light years away from the Sun based on parallax.[1] It is visible to the naked eye as a dim, white-hued star with a combined apparent visual magnitude of 5.00.[2] The system is moving further away from the Earth with a heliocentric radial velocity of +4.36 km/s.[1] It is a suspected member of the Ursa Major Moving Group stream.[10]

Cowley et al. (1969) found a stellar classification of A7 V[5] for the visible component, matching an A-type main-sequence star that is generating energy through hydrogen fusion at its core. Abt and Morrell (1995) instead listed a class of A6 IV,[4] suggesting it has left the main sequence and become a subgiant star.

16 Lyrae is 72% more massive than the Sun and irradiates 10.5 times the Sun's luminosity. It is 401 million years old with a high rate of spin, showing a projected rotational velocity of 85 km/s. The fast rotation make this star slightly oblate, with an equatorial radius of 1.644 R and a polar radius of 1.622 R. Its effective temperature also vary acrooss its surface due to rotation, from 8,200 K in the poles to 8,000 K in the equator.[6]

This system is a source for X-ray emission with a luminosity of 105.3×1020 W, which is most likely coming from the unseen companion.[11]

References

[edit]
  1. ^ a b c d e f g Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv:2208.00211. Bibcode:2023A&A...674A...1G. doi:10.1051/0004-6361/202243940. S2CID 244398875. Gaia DR3 record for this source at VizieR.
  2. ^ 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.
  3. ^ Zorec, J.; Royer, F. (2012), "Rotational velocities of A-type stars. IV. Evolution of rotational velocities", Astronomy & Astrophysics, 537: A120, arXiv:1201.2052, Bibcode:2012A&A...537A.120Z, doi:10.1051/0004-6361/201117691, S2CID 55586789, A120.
  4. ^ a b Abt, Helmut A.; Morrell, Nidia I (1995), "The Relation between Rotational Velocities and Spectral Peculiarities among A-Type Stars", Astrophysical Journal Supplement, 99: 135, Bibcode:1995ApJS...99..135A, doi:10.1086/192182
  5. ^ a b Cowley, A.; et al. (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.
  6. ^ a b Jones, Jeremy; White, R. J.; Boyajian, T.; Schaefer, G.; Baines, E.; Ireland, M.; Patience, J.; Brummelaar, T. ten; McAlister, H.; Ridgway, S. T.; Sturmann, J.; Sturmann, L.; Turner, N.; Farrington, C.; Goldfinger, P. J. (2015-10-28), "The Ages of A-Stars I: Interferometric Observations and Age Estimates for Stars in the Ursa Major Moving Group", The Astrophysical Journal, 813 (1): 58, arXiv:1508.05643, Bibcode:2015ApJ...813...58J, doi:10.1088/0004-637X/813/1/58, ISSN 1538-4357
  7. ^ 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.
  8. ^ a b "16 Lyr". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2019-05-28.
  9. ^ Eggleton, P. P.; Tokovinin, A. A. (September 2008), "A catalogue of multiplicity among bright stellar systems", Monthly Notices of the Royal Astronomical Society, 389 (2): 869–879, arXiv:0806.2878, Bibcode:2008MNRAS.389..869E, doi:10.1111/j.1365-2966.2008.13596.x, S2CID 14878976.
  10. ^ King, Jeremy R.; et al. (2003), "Stellar Kinematic Groups. II. A Reexamination of the Membership, Activity, and Age of the Ursa Major Group", The Astronomical Journal, 125 (4): 1980, Bibcode:2003AJ....125.1980K, doi:10.1086/368241
  11. ^ Schröder, C.; Schmitt, J. H. M. M. (November 2007), "X-ray emission from A-type stars", Astronomy and Astrophysics, 475 (2): 677–684, Bibcode:2007A&A...475..677S, doi:10.1051/0004-6361:20077429.