19 Lyrae

19 Lyrae is a single^[10] variable star located approximately 950^[2] light years away from the Sun in the northern constellation of Lyra.^[9] It has the variable star designation V471 Lyr, while 19 Lyrae is the Flamsteed designation. This object is just bright enough to be visible to the naked eye, appearing as a dim, blue-white star with a baseline apparent visual magnitude of 5.93.^[3] It is moving closer to the Earth with a heliocentric radial velocity of −30 km/s, and may come as close as 167 light-years around 8.5 million years from now.^[3]

19 Lyrae

A light curve for 19 Lyrae, plotted from TESS data[1]
Observation data Epoch J2000.0      Equinox J2000.0
Constellation	Lyra
Right ascension	19h 11m 46.008s[2]
Declination	+31° 17′ 00.44″[2]
Apparent magnitude (V)	5.93[3]
Characteristics
Spectral type	B8 IIIp Si Sr[4]
B−V color index	−0.062±0.004[3]
Variable type	α2 CVn[5]
Astrometry
Radial velocity (Rv)	−30.1±2.9[3] km/s
Proper motion (μ)	RA: −4.143 mas/yr[2] Dec.: −2.763 mas/yr[2]
Parallax (π)	3.4213 ± 0.0417 mas[2]
Distance	950 ± 10 ly (292 ± 4 pc)
Absolute magnitude (MV)	−1.24[3]
Details
Mass	3.76±0.22[6] M☉
Radius	6.40[7] R☉
Luminosity	397.48[3] L☉
Temperature	11,194+501 −479[6] K
Rotational velocity (v sin i)	35[8] km/s
Other designations
19 Lyr, V471 Lyr, NSV 11806, BD+31°3497, FK5 3532, GC 26459, HD 179527, HIP 94311, HR 7283, SAO 67946[9]
Database references
SIMBAD	data

This is a magnetic chemically-peculiar star^[11] with a stellar classification of B8 IIIp Si Sr,^[4] showing abundance anomalies in silicon and strontium. The light variations of this star were discovered by J. E. Winzer in 1974.^[12] It is an Alpha² Canum Venaticorum-type variable with a period of 1.160898 days (or 7.0980 days^[12]), ranging in magnitude from a high of 5.91 down to 5.98.^[5] The surface magnetic field has a strength of (111.3±56.9)×10⁻⁴ T^[13]

19 Lyrae has a moderate rotation rate, showing a projected rotational velocity of 35 km/s.^[8] Stellar models give it an estimated 3.8^[6] times the mass of the Sun and its girth is measured at 6.4^[7] times the Sun's radius. It is radiating 397^[3] times the luminosity of the Sun from its photosphere at an effective temperature of around 11,194 K.^[6] The star has an absolute magnitude of −1.24,^[3] which shows how bright the star would appear if it were located at a distance of 10 parsecs (33 ly) from the Sun.

References

1. MAST: Barbara A. Mikulski Archive for Space Telescopes, Space Telescope Science Institute, retrieved 8 December 2021.
2. 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.
3. 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.
4. 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. 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.
6. Netopil, Martin; et al. (July 2017), "An Investigation of the Rotational Properties of Magnetic Chemically Peculiar Stars", Monthly Notices of the Royal Astronomical Society, 468 (3): 2745–2756, arXiv:1703.05218, Bibcode:2017MNRAS.468.2745N, doi:10.1093/mnras/stx674.
7. Shulyak, D.; et al. (2014), "Interferometry of chemically peculiar stars: Theoretical predictions versus modern observing facilities", Monthly Notices of the Royal Astronomical Society, 443 (2): 1629, arXiv:1406.6093, Bibcode:2014MNRAS.443.1629S, doi:10.1093/mnras/stu1259.
8. Abt, Helmut A.; et al. (July 2002), "Rotational Velocities of B Stars", The Astrophysical Journal, 573 (1): 359–365, Bibcode:2002ApJ...573..359A, doi:10.1086/340590
9. "19 Lyr". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2019-05-30.
10. Eggleton, P. P.; Tokovinin, A. A. (2008), "A catalogue of multiplicity among bright stellar systems", Monthly Notices of the Royal Astronomical Society, 389 (2): 869, arXiv:0806.2878, Bibcode:2008MNRAS.389..869E, doi:10.1111/j.1365-2966.2008.13596.x, S2CID 14878976.
11. Kochukhov, O.; Bagnulo, S. (2006), "Evolutionary state of magnetic chemically peculiar stars", Astronomy and Astrophysics, 450 (2): 763, arXiv:astro-ph/0601461, Bibcode:2006A&A...450..763K, doi:10.1051/0004-6361:20054596, S2CID 18596834
12. Adelman, S. J.; Rice, R. H. (April 1999), "UVBY photometry of the mCP stars HD 35298, 19 Lyrae, HD 192678, and HR 8216", Astronomy and Astrophysics Supplement, 136: 111–115, Bibcode:1999A&AS..136..111A, doi:10.1051/aas:1999202.
13. Bychkov, V. D.; et al. (2009), "Catalogue of averaged stellar effective magnetic fields - II. Re-discussion of chemically peculiar A and B stars", Monthly Notices of the Royal Astronomical Society, 394 (3): 1338, Bibcode:2009MNRAS.394.1338B, doi:10.1111/j.1365-2966.2008.14227.x, S2CID 120268049.