16 Lyrae
Astrometric binary star system in the constellation Lyra
16 Lyrae is a suspected astrometric binary [ 8] star system in the constellation Lyra ,[ 7] 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 +5 km/s.[ 2] It is a suspected member of the Ursa Major Moving Group stream.[ 9]
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 . It is 791[ 6] million years old with a high rate of spin, showing a projected rotational velocity of 124 km/s.[ 3] 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.[ 10]
References
^ a b c d e f g h i Brown, A. G. A. ; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties" . Astronomy & Astrophysics . 616 . A1. arXiv :1804.09365 . Bibcode :2018A&A...616A...1G . doi :10.1051/0004-6361/201833051 . Gaia DR2 record for this source at VizieR .
^ 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 c d 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.
^ 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
^ 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 .
^ a b c 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 "16 Lyr" . SIMBAD . Centre de données astronomiques de Strasbourg . Retrieved 2019-05-28 .
^ 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 . {{citation }}
: CS1 maint: unflagged free DOI (link )
^ 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
^ 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 .