6 Lacertae

6 Lacertae is a binary star[5] system in the northern constellation of Lacerta, located around 1,900 light years from the Sun.[1] It is visible to the naked eye as a dim, blue-white hued star with a combined apparent visual magnitude of 4.52.[2] The system is moving closer to the Earth with a heliocentric radial velocity of −9 km/s,[2] and is a suspected member of the Lac OB1 association.[4]

6 Lacertae
Observation data
Epoch J2000      Equinox J2000
Constellation Lacerta
Right ascension 22h 30m 29.26005s[1]
Declination +43° 07′ 24.1565″[1]
Apparent magnitude (V) 4.52[2]
Characteristics
Spectral type B2 IV[3]
B−V color index −0.086±0.018[2]
Astrometry
Radial velocity (Rv)−8.7±0.9[2] km/s
Proper motion (μ) RA: −4.800[1] mas/yr
Dec.: −2.598[1] mas/yr
Parallax (π)1.7577 ± 0.2697[1] mas
Distanceapprox. 1,900 ly
(approx. 570 pc)
Absolute magnitude (MV)−2.62[4]
Orbit[5]
Period (P)880 days
Eccentricity (e)0.30
Periastron epoch (T)2,416,300 JD
Argument of periastron (ω)
(secondary)		190°
Semi-amplitude (K1)
(primary)		9 km/s
Details
Mass12.5±0.6[6] M☉
Radius6.9[7] R☉
Luminosity (bolometric)34,590[8] L☉
Surface gravity (log g)3.56[9] cgs
Temperature21,150[8] K
Metallicity [Fe/H]−0.04[9] dex
Rotational velocity (v sin i)70[10] km/s
Age15.7±0.1[6] Myr
Other designations
6 Lac, BD+42° 4420, FK5 3800, HD 213420, HIP 111104, HR 8579, SAO 52079[11]
Database references
SIMBADdata

This system forms a single-lined spectroscopic binary with an orbital period of 880 days and an eccentricity of 0.3.[5] The visible component has a stellar classification of B2 IV,[3] matching a B-type subgiant star. It is about 16[6] million years old with a relatively high projected rotational velocity of 70 km/s.[10] The star has 12.5[6] times the mass of the Sun and about 7[7] times the Sun's radius. It is radiating a net 34,590[8] times the Sun's luminosity from its photosphere at an effective temperature of 21,150 K.[8]

References
  1. 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.
  2. 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.
  3. Lesh, Janet Rountree (December 1968), "The Kinematics of the Gould Belt: an Expanding Group?", Astrophysical Journal Supplement, 17: 371, Bibcode:1968ApJS...17..371L, doi:10.1086/190179
  4. Kaltcheva, Nadia (October 2009), "Lacerta OB1 Revisited", Publications of the Astronomical Society of the Pacific, 121 (884): 1045, Bibcode:2009PASP..121.1045K, doi:10.1086/606037.
  5. Beardsley, Wallace R. (1969), "The Radial Velocities of 129 Stars in the Years 1906 to 1917", Publications of the Allegheny Observatory of the University of Pittsburgh, 7: 91–263, Bibcode:1969PAllO...8...91B.
  6. Tetzlaff, N.; et al. (January 2011), "A catalogue of young runaway Hipparcos stars within 3 kpc from the Sun", Monthly Notices of the Royal Astronomical Society, 410 (1): 190–200, arXiv:1007.4883, Bibcode:2011MNRAS.410..190T, doi:10.1111/j.1365-2966.2010.17434.x.
  7. Pasinetti Fracassini, L. E.; et al. (February 2001), "Catalogue of Apparent Diameters and Absolute Radii of Stars (CADARS)", Astronomy and Astrophysics (Third ed.), 367: 521–524, arXiv:astro-ph/0012289, Bibcode:2001A&A...367..521P, doi:10.1051/0004-6361:20000451.
  8. Hohle, M. M.; et al. (April 2010), "Masses and luminosities of O- and B-type stars and red supergiants", Astronomische Nachrichten, 331 (4): 349, arXiv:1003.2335, Bibcode:2010AN....331..349H, doi:10.1002/asna.200911355.
  9. Gies, Douglas R.; Lambert, David L. (March 1992), "Carbon, Nitrogen, and Oxygen Abundances in Early B-Type Stars", Astrophysical Journal, 387: 673, Bibcode:1992ApJ...387..673G, doi:10.1086/171116.
  10. Strom, Stephen E.; et al. (2005), "B Star Rotational Velocities in h and χ Persei: A Probe of Initial Conditions during the Star Formation Epoch?", The Astronomical Journal, 129 (2): 809–828, arXiv:astro-ph/0410337, Bibcode:2005AJ....129..809S, doi:10.1086/426748.
  11. "6 Lac". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2019-01-28.
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