HY Velorum is a binary star[7] system in the southern constellation of Vela. It is a dim star but visible to the naked eye with an apparent visual magnitude of 4.83.[5] The distance to this system, as estimated from its annual parallax shift of 7.1 mas,[2] is 460 light years. HY Vel most likely forms a gravitationally bound pair with the magnitude 5.45 binary system KT Vel (HD 74535);[12] both are members of the IC 2391 open cluster.[13] As of 1998, HY Vel and KT Vel had an angular separation of 76.1″ along a position angle of 311°.[14]
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Vela |
| Right ascension | 08h 42m 25.38667s[2] |
| Declination | −53° 06′ 50.3324″[2] |
| Apparent magnitude (V) | 4.81 - 4.86[3] |
| Characteristics | |
| Spectral type | B3 IV[4] |
| B−V color index | −0.173±0.007[5] |
| Variable type | SPB[3] |
| Astrometry | |
| Radial velocity (Rv) | +15.6±0.2[5] km/s |
| Proper motion (μ) | RA: −24.83[6] mas/yr Dec.: +23.21[6] mas/yr |
| Parallax (π) | 7.1141 ± 0.2302 mas[2] |
| Distance | 460 ± 10 ly (141 ± 5 pc) |
| Absolute magnitude (MV) | −1.25[5] |
| Orbit[7] | |
| Period (P) | 8.378±0.001 d |
| Eccentricity (e) | 0.24±0.04 |
| Periastron epoch (T) | 2450741.3 ± 0.2 HJD |
| Argument of periastron (ω) (secondary) | 93±9° |
| Semi-amplitude (K1) (primary) | 8.0±0.3 km/s |
| Details | |
| HY Vel Aa | |
| Mass | 5.4[8] M☉ |
| Luminosity | 830+927 −743[8] L☉ |
| Surface gravity (log g) | 4.07[9] cgs |
| Temperature | 16,865+235 −231[8] K |
| Metallicity [Fe/H] | 0.03±0.02[9] dex |
| Rotational velocity (v sin i) | 45[8] km/s |
| Age | 179[10] Myr |
| Other designations | |
| Database references | |
| SIMBAD | data |
This is a single-lined spectroscopic binary system with an orbital period of 8.4 days and an eccentricity of 0.24. The visible component has an a sin i value of 0.006 AU, where a is the semimajor axis and i is the (unknown) orbital inclination to the line of sight.
The primary is a slowly pulsating B-type star having at least three pulsational modes, with the dominant mode showing a frequency of 0.64472 cycles per day,[7] corresponding to the catalogued period of 1.55106 days.[3] It has a stellar classification of B3 IV, matching a B-type subgiant star.[4]
References
edit- ^ Waelkens, C.; Rufener, F. (November 1985). "Photometric variability of mid-B stars". Astronomy and Astrophysics. 152: 6–14. Bibcode:1985A&A...152....6W. Retrieved 30 April 2022.
- ^ a b c d 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.
- ^ a b c Samus, N. N.; Durlevich, O. V.; et al. (2009). "VizieR Online Data Catalog: General Catalogue of Variable Stars (Samus+ 2007-2013)". VizieR On-line Data Catalog: B/GCVS. Originally Published in: 2009yCat....102025S. 1. Bibcode:2009yCat....102025S.
- ^ a b 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.
- ^ a b c d 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.
- ^ a b van Leeuwen, F. (November 2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics, 474 (2): 653–664, arXiv:0708.1752, Bibcode:2007A&A...474..653V, doi:10.1051/0004-6361:20078357, S2CID 18759600.
- ^ a b c De Cat, P.; Aerts, C.; De Ridder, J.; Kolenberg, K.; Meeus, G.; Decin, L. (2000), "A study of bright southern slowly pulsating B stars. I. Determination of the orbital parameters and of the main frequency of the spectroscopic binaries", Astronomy and Astrophysics, 355: 1015–1030, Bibcode:2000A&A...355.1015D.
- ^ a b c d Szewczuk, W.; Daszyńska-Daszkiewicz, J. (June 2015), "Identification of pulsational modes in rotating slowly pulsating B-type stars", Monthly Notices of the Royal Astronomical Society, 450 (2): 1585–1603, arXiv:1504.04490, Bibcode:2015MNRAS.450.1585S, doi:10.1093/mnras/stv715, S2CID 119194953.
- ^ a b Niemczura, E. (June 2003), "Metallicities of the SPB stars from the IUE ultraviolet spectra", Astronomy and Astrophysics, 404 (2): 689–700, Bibcode:2003A&A...404..689N, doi:10.1051/0004-6361:20030546.
- ^ Gontcharov, G. A. (November 2012), "Spatial distribution and kinematics of OB stars", Astronomy Letters, 38 (11): 694–706, arXiv:1606.09028, Bibcode:2012AstL...38..694G, doi:10.1134/S1063773712110035, S2CID 119108982.
- ^ "HD 74560". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 16 August 2018.
- ^ 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.
- ^ Dodd, R. J. (April 2007), "Unified Absolute Spectrophotometry for Star Clusters", in Sterken, C. (ed.), The Future of Photometric, Spectrophotometric and Polarimetric Standardization. Proceedings of a conference held 8-11 May, 2006 in Blankenberge, Belgium, ASP Conference Series, vol. 364, San Francisco: Astronomical Society of the Pacific, p. 237, Bibcode:2007ASPC..364..237D.
- ^ Mason, B. D.; et al. (2014), "The Washington Visual Double Star Catalog", The Astronomical Journal, 122 (6): 3466–3471, Bibcode:2001AJ....122.3466M, doi:10.1086/323920