Astronomy:HD 83953
| Observation data Equinox J2000.0]] (ICRS) | |
|---|---|
| Constellation | Hydra |
| Right ascension | 09h 41m 17.00785s[1] |
| Declination | −23° 35′ 29.4325″[1] |
| Apparent magnitude (V) | 4.76[2] |
| Characteristics | |
| Spectral type | B5 V[3] |
| B−V color index | −0.117±0.015[2] |
| Astrometry | |
| Radial velocity (Rv) | +16.05±1.5[4] km/s |
| Proper motion (μ) | RA: −29.969[1] mas/yr Dec.: +1.914[1] mas/yr |
| Parallax (π) | 6.5733 ± 0.2851[1] mas |
| Distance | 500 ± 20 ly (152 ± 7 pc) |
| Absolute magnitude (MV) | −1.19[2] |
| Details | |
| Mass | 4.57±0.08[5] M☉ |
| Radius | 4.00±0.08[6] R☉ |
| Luminosity | 708+60 −55[5] L☉ |
| Surface gravity (log g) | 2.54±0.03[6] cgs |
| Temperature | 15,000±150[6] K |
| Rotational velocity (v sin i) | 315[5][7] km/s |
| Other designations | |
| Database references | |
| SIMBAD | data |
HD 83953 (I Hydrae) is a single,[9] blue-white hued star in the equatorial constellation of Hydra. It is visible to the naked eye, having an apparent visual magnitude of 4.76.[2] Based upon an annual parallax shift of 6.6 mas,[1] the distance to this star is estimated as 500 light years. It is moving further from Earth with a heliocentric radial velocity of +16 km/s.[4]
This is a B-type main-sequence star with a stellar classification of B5 V.[3] It has been known to be a Be star since 1926, when an Hβ emission line was discovered in the stellar spectrum by Mount Wilson Observatory.[10] This energy is coming from a circumstellar envelope of heated gas that has been expelled from the central star and formed a thin orbiting disk.[11] HD 83953 is spinning rapidly with a projected rotational velocity of 315 km/s, giving the star an oblate shape with an equatorial bulge that is 18% larger than the polar radius.[7]
HD 83953 has 4.6[5] times the mass of the Sun and 4.0[6] times the Sun's radius. It is radiating 708[5] times the Sun's luminosity from its photosphere at an effective temperature of 15,000 K.[6]
References
- ↑ 1.0 1.1 1.2 1.3 1.4 1.5 Brown, A. G. A. (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics 616: A1. doi:10.1051/0004-6361/201833051. Bibcode: 2018A&A...616A...1G.
- ↑ 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.
- ↑ 3.0 3.1 Houk, Nancy; Smith-Moore, M. (1978), Michigan catalogue of two-dimensional spectral types for the HD stars, 4, Ann Arbor: Dept. of Astronomy, University of Michigan, Bibcode: 1988mcts.book.....H.
- ↑ 4.0 4.1 Becker, Juliette C. et al. (April 2015), "Extracting Radial Velocities of A- and B-type Stars from Echelle Spectrograph Calibration Spectra", The Astrophysical Journal Supplement Series 217 (2): 13, doi:10.1088/0067-0049/217/2/29, 29, Bibcode: 2015ApJS..217...29B.
- ↑ 5.0 5.1 5.2 5.3 5.4 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, Bibcode: 2012A&A...537A.120Z.
- ↑ 6.0 6.1 6.2 6.3 6.4 Arcos, C. et al. (March 2018), "Stellar parameters and H α line profile variability of Be stars in the BeSOS survey", Monthly Notices of the Royal Astronomical Society 474 (4): 5287–5299, doi:10.1093/mnras/stx3075, Bibcode: 2018MNRAS.474.5287A.
- ↑ 7.0 7.1 Belle, G. T. (2012), "Interferometric observations of rapidly rotating stars", The Astronomy and Astrophysics Review 20 (1): 51, doi:10.1007/s00159-012-0051-2, Bibcode: 2012A&ARv..20...51V.
- ↑ "HD 83953". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=HD+83953.
- ↑ 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, doi:10.1111/j.1365-2966.2008.13596.x, Bibcode: 2008MNRAS.389..869E.
- ↑ Merrill, Paul W.; Burwell, Cora G. (September 1933), "Catalogue and Bibliography of Stars of Classes B and A whose Spectra have Bright Hydrogen Lines", Astrophysical Journal 78: 87, doi:10.1086/143490, Bibcode: 1933ApJ....78...87M.
- ↑ Arcos, C. et al. (June 2017), "Evidence for Different Disk Mass Distributions Between Early and Late-Type Be Stars in the BeSOS Survey", The Astrophysical Journal 842 (1): 18, doi:10.3847/1538-4357/aa6f5f, 48, Bibcode: 2017ApJ...842...48A.
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