HD 89998

HD 89998 (r Velorum) is a single[8] star in the southern constellation of Vela. It is a faint star but visible to the naked eye with an apparent visual magnitude of 4.82.[2] The distance to HD 89998, as determined from its annual parallax shift of 15.9 mas,[1] is 205 light years. The star is moving further from the Earth with a heliocentric radial velocity of +21 km/s,[4] having come within 140 ly some 1.552 million years ago.[2]

HD 89998
Observation data
Epoch J2000      Equinox J2000
Constellation Vela
Right ascension 10h 22m 19.58477s[1]
Declination −41° 38 59.8592[1]
Apparent magnitude (V) 4.82[2]
Characteristics
Spectral type K1 III[3]
B−V color index 1.095±0.055[2]
Astrometry
Radial velocity (Rv)+20.9±0.8[4] km/s
Proper motion (μ) RA: −27.664[1] mas/yr
Dec.: +60.090[1] mas/yr
Parallax (π)15.9154 ± 0.1375 mas[1]
Distance205 ± 2 ly
(62.8 ± 0.5 pc)
Absolute magnitude (MV)0.84[2]
Details
Radius11.6[5] R
Luminosity54.04[6] L
Temperature4,812[6] K
Other designations
r Vel, NSV 4837, CD−41° 5809, FK5 1268, HD 89998, HIP 50799, HR 4080, SAO 221998[7]
Database references
SIMBADdata

This is an evolved giant star with a stellar classification of K1 III.[3] The measured angular diameter of this star, after correcting for limb darkening, is 1.72±0.02 mas.[9] At the estimated distance of this star, this yields a physical size of 11.6 times the radius of the Sun.[5] It is radiating 54[6] times the Sun's luminosity from its enlarged photosphere at en effective temperature of 4,812 K.[6]

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, S2CID 119257644.
  3. Houk, Nancy (1978), Michigan catalogue of two-dimensional spectral types for the HD stars, vol. 2, Ann Arbor: Dept. of Astronomy, University of Michigan, Bibcode:1978mcts.book.....H.
  4. 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, S2CID 59451347, A61.
  5. Lang, Kenneth R. (2006), Astrophysical formulae, Astronomy and astrophysics library, vol. 1 (3rd ed.), Birkhäuser, ISBN 3-540-29692-1. The radius (R*) is given by:
  6. McDonald, I.; et al. (2012), "Fundamental parameters and infrared excesses of Hipparcos stars", Monthly Notices of the Royal Astronomical Society, 427 (1): 343–357, arXiv:1208.2037, Bibcode:2012MNRAS.427..343M, doi:10.1111/j.1365-2966.2012.21873.x, S2CID 118665352.
  7. "HD 85622". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2018-08-08.
  8. 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.
  9. Richichi, A.; et al. (February 2005), "CHARM2: An updated Catalog of High Angular Resolution Measurements", Astronomy and Astrophysics, 431 (2): 773–777, Bibcode:2005A&A...431..773R, doi:10.1051/0004-6361:20042039.
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