HD 83446

HD 83446 is a probable astrometric binary[10] star system in the constellation Vela. It is visible to the naked eye with an apparent visual magnitude of 4.34.[2] Based upon an annual parallax shift of 30.5 mas,[1] it is located 107.1 light years from the Sun. The system is moving further away with a heliocentric radial velocity of +18 km/s.[6]

This article is about M Velorum. For m Velorum, see HD 85622.
HD 85622
Observation data
Epoch J2000      Equinox J2000
Constellation Vela
Right ascension  09h 36m 49.53851s[1]
Declination −49° 21′ 18.0873″[1]
Apparent magnitude (V) 4.34[2]
Characteristics
Evolutionary stage main sequence[3]
Spectral type A7 V[4]
B−V color index 0.173±0.005[2]
Variable type δ Sct[5]
Astrometry
Radial velocity (Rv)+17.8±0.5[6] km/s
Proper motion (μ) RA: −130.55[1] mas/yr
Dec.: +42.98[1] mas/yr
Parallax (π)30.4562 ± 0.1933[1] mas
Distance107.1 ± 0.7 ly
(32.8 ± 0.2 pc)
Absolute magnitude (MV)1.79[2]
Details
Mass1.8+0.11
−0.09[7] M☉
Luminosity15.99[2] L☉
Surface gravity (log g)4.3±0.14[7] cgs
Temperature8,331±283[7] K
Rotational velocity (v sin i)155[8] km/s
Age453+256
−278[7] Myr
Other designations
M Vel, CD−48° 4836, FK5 2768, HD 83446, HIP 47175, HR 3836, SAO 221344[9]
Database references
SIMBADdata

The visible component is an A-type main-sequence star with a stellar classification of A7 V.[4] Observations with the BRITE constellation led to this star's identification as a Delta Scuti variable with pulsation periods of 31.0806 and 34.2098 days.[5] It has a high rate of spin with a projected rotational velocity of 155 km/s, which is giving the star an oblate shape with an equatorial bulge that is 6% larger than the polar radius.[8] The star is roughly 453[7] million years old with 1.8[7] times the mass of the Sun. It is radiating 16[2] times the Sun's luminosity from its photosphere at an effective temperature of 8,331 K.[7]

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. 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.
  4. Gray, R. O.; et al. (July 2006), "Contributions to the Nearby Stars (NStars) Project: spectroscopy of stars earlier than M0 within 40 pc-The Southern Sample", The Astronomical Journal, 132 (1): 161–170, arXiv:astro-ph/0603770, Bibcode:2006AJ....132..161G, doi:10.1086/504637.
  5. Zwintz, K. (September 2017), "A BRITE view on δ Scuti and γ Doradus stars", in Zwintz, Konnstanze; Poretti, Ennio (eds.), Second BRITE-Constellation Science Conference: Small satellites—big science, Proceedings of the Polish Astronomical Society volume 5, held 22-26 August, 2016 in Innsbruck, Austria, Bartycka 18, 00-716 Warsaw, Poland: Polish Astronomical Society, pp. 228–235, arXiv:1611.04917, Bibcode:2017sbcs.conf..228ZCS1 maint: location (link)
  6. de Bruijne, J. H. J.; Eilers, A.-C. (October 2012), "Radial velocities for the HIPPARCOS-Gaia Hundred-Thousand-Proper-Motion project", Astronomy & Astrophysics, 546: 14, arXiv:1208.3048, Bibcode:2012A&A...546A..61D, doi:10.1051/0004-6361/201219219, A61.
  7. Gullikson, Kevin; et al. (2016), "The Close Companion Mass-Ratio Distribution of Intermediate-Mass Stars", The Astronomical Journal, 152 (2): 40, arXiv:1604.06456, Bibcode:2016AJ....152...40G, doi:10.3847/0004-6256/152/2/40.
  8. Belle, G. T. (2012), "Interferometric observations of rapidly rotating stars", The Astronomy and Astrophysics Review, 20: 51, arXiv:1204.2572, Bibcode:2012A&ARv..20...51V, doi:10.1007/s00159-012-0051-2.
  9. "HD 83446". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2018-08-08.
  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.
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