Astronomy:16 Lyrae
| Observation data Equinox J2000.0]] (ICRS) | |
|---|---|
| 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[1] mas/yr Dec.: −80.894[1] mas/yr |
| Parallax (π) | 25.7832 ± 0.0688[1] mas |
| Distance | 126.5 ± 0.3 ly (38.8 ± 0.1 pc) |
| Absolute magnitude (MV) | +2.13[2] |
| Details[6] | |
| Mass | 1.722±0.013 M☉ |
| Radius | 1.644+0.025 −0.023 (equatorial) 1.622+0.023 −0.022 (polar) R☉ |
| Luminosity | 10.45+0.30 −0.28 L☉ |
| Surface gravity (log g) | 4.28[7] cgs |
| Temperature | 8,028 (equator) 8,242 (polar) K |
| Rotational velocity (v sin i) | 85.1+16.3 −31.6 km/s |
| Age | 401+31 −32 Myr |
| Other designations | |
| Database references | |
| SIMBAD | data |
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 across 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
- ↑ 1.0 1.1 1.2 1.3 1.4 1.5 1.6 Vallenari, A. et al. (2022). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy & Astrophysics. doi:10.1051/0004-6361/202243940 Gaia DR3 record for this source at VizieR.
- ↑ 2.0 2.1 2.2 2.3 Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters 38 (5): 331, doi:10.1134/S1063773712050015, Bibcode: 2012AstL...38..331A.
- ↑ Zorec, J.; Royer, F. (2012), "Rotational velocities of A-type stars. IV. Evolution of rotational velocities", Astronomy & Astrophysics 537: A120, doi:10.1051/0004-6361/201117691, A120, Bibcode: 2012A&A...537A.120Z.
- ↑ 4.0 4.1 Abt, Helmut A.; Morrell, Nidia I (1995), "The Relation between Rotational Velocities and Spectral Peculiarities among A-Type Stars", Astrophysical Journal Supplement 99: 135, doi:10.1086/192182, Bibcode: 1995ApJS...99..135A
- ↑ 5.0 5.1 Cowley, A. et al. (April 1969), "A study of the bright A stars. I. A catalogue of spectral classifications", Astronomical Journal 74: 375–406, doi:10.1086/110819, Bibcode: 1969AJ.....74..375C.
- ↑ 6.0 6.1 Jones, Jeremy; White, R. J.; Boyajian, T.; Schaefer, G.; Baines, E.; Ireland, M.; Patience, J.; Brummelaar, T. ten et al. (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, doi:10.1088/0004-637X/813/1/58, ISSN 1538-4357, Bibcode: 2015ApJ...813...58J
- ↑ 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, doi:10.1088/0004-637X/804/2/146, Bibcode: 2015ApJ...804..146D.
- ↑ 8.0 8.1 "16 Lyr". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=16+Lyr.
- ↑ 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, doi:10.1111/j.1365-2966.2008.13596.x, Bibcode: 2008MNRAS.389..869E.
- ↑ 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, doi:10.1086/368241, Bibcode: 2003AJ....125.1980K, https://tigerprints.clemson.edu/cgi/viewcontent.cgi?article=1248&context=physastro_pubs
- ↑ 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, Bibcode: 2007A&A...475..677S.
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