16 Lyrae

Astrometric binary star system in the constellation Lyra J2000.0 Lyra 19 01 26.38262 +46 56 05.1475 5.00 main sequence A6 IV or A7 V +0.186 0.005 +4.36 0.21 +22.004 -80.894 25.7832 0.0688 +2.13 1.722 0.013 1.644 0.025 0.023 (equatorial)1.622 0.023 0.022 (polar) 4.28 10.45 0.30 0.28 8,028 (equator)8,242 (polar) 85.1 16.3 31.6 401 31 32 16 Lyr 11677 +46°2602 177196 93408 7215 48011 03545-03041 J19014+4656A 16+Lyr 16 Lyrae is a suspected astrometric binary star system in the constellation Lyra, located 126 light years away from the Sun based on parallax. It is visible to the naked eye as a dim, white-hued star with a combined apparent visual magnitude of 5.00. The system is moving further away from the Earth with a heliocentric radial velocity of +4.36 km/s. It is a suspected member of the Ursa Major Moving Group stream. Cowley et al. (1969) found a stellar classification of A7 V 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, 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 and a polar radius of 1.622. Its effective temperature also vary across its surface due to rotation, from K 8200 commas in the poles to K 8000 commas in the equator. This system is a source for X-ray emission with a luminosity of 105.3e20 W, which is most likely coming from the unseen companion. References 30em 2131342100048643584 16 Lyr 2019-05-28 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 1508.05643 The Astrophysical Journal 813 1 58 10.1088/0004-637X/813/1/58 2015ApJ...813...58J 1538-4357 Eggleton P. P. Tokovinin A. A. A catalogue of multiplicity among bright stellar systems Monthly Notices of the Royal Astronomical Society 389 2 869–879 September 2008 10.1111/j.1365-2966.2008.13596.x free . 2008MNRAS.389..869E 0806.2878 14878976 Abt Helmut A. Morrell Nidia I The Relation between Rotational Velocities and Spectral Peculiarities among A-Type Stars Astrophysical Journal Supplement 99 135 1995 10.1086/192182 1995ApJS...99..135A free XHIP: An extended hipparcos compilation Anderson E. Francis Ch. Astronomy Letters . 38 5 331 2012 2012AstL...38..331A 1108.4971 10.1134/S1063773712050015 119257644 X-ray emission from A-type stars Schröder C. Schmitt J. H. M. M. Astronomy and Astrophysics . 475 2 November 2007 677–684 10.1051/0004-6361:20077429 2007A&A...475..677S free Rotational velocities of A-type stars. IV. Evolution of rotational velocities Astronomy & Astrophysics 537 A120 2012 Zorec J. Royer F. A120 10.1051/0004-6361/201117691 2012A&A...537A.120Z 1201.2052 55586789 . David Trevor J. Hillenbrand Lynne A. 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 2015 2015ApJ...804..146D 1501.03154 10.1088/0004-637X/804/2/146 33401607 . 1 King Jeremy R. Villarreal Adam R. Soderblom David R. Gulliver Austin F. Adelman Saul J. Stellar Kinematic Groups. II. A Reexamination of the Membership, Activity, and Age of the Ursa Major Group The Astronomical Journal 125 4 1980 2003 10.1086/368241 2003AJ....125.1980K https://tigerprints.clemson.edu/cgi/viewcontent.cgi?article=1248&context=physastro_pubs free subscription . Cowley A. Cowley C. Jaschek M. Jaschek C. A study of the bright A stars. I. A catalogue of spectral classifications 1 Astronomical Journal 74 375–406 April 1969 10.1086/110819 1969AJ.....74..375C Category:A-type main-sequence stars Category:A-type subgiants Category:Astrometric binaries Category:Lyra Category:Durchmusterung objects Lyrae, 16 177196 093408 7215 Category:Suspected variables Category:Ursa Major moving group