Astronomy:HD 119921
| Observation data Equinox J2000.0]] (ICRS) | |
|---|---|
| Constellation | Centaurus |
| Right ascension | 13h 46m 56.35149s[1] |
| Declination | –36° 15′ 06.9563″[1] |
| Apparent magnitude (V) | 5.15[2] |
| Characteristics | |
| Spectral type | A0 V[3][4] or B9.5 III-n[5] |
| Astrometry | |
| Radial velocity (Rv) | −9.8±2.8[6] km/s |
| Proper motion (μ) | RA: −13.293[1] mas/yr Dec.: −11.115[1] mas/yr |
| Parallax (π) | 7.7881 ± 0.2382[1] mas |
| Distance | 420 ± 10 ly (128 ± 4 pc) |
| Absolute magnitude (MV) | 0.93[7] |
| Details | |
| Luminosity | 125.24[8] L☉ |
| Temperature | 8,801[8] K |
| Rotational velocity (v sin i) | 220[9] km/s |
| Age | 337[7] Myr |
| Other designations | |
| Database references | |
| SIMBAD | data |
HD 119921 is a single,[4] white-hued star in the southern constellation of Centaurus. it has the Bayer designation z Centauri. This is faintly visible to the naked eye, having an apparent visual magnitude of 5.15.[2] It forms a wide double star with a faint, magnitude 12.50 visual companion, which is located at an angular separation of 27.20″ as of 2010.[11] HD 119921 is moving closer to us with a heliocentric radial velocity of around −10 km/s,[6] and is currently located some 420±10 light year from the Sun. At that distance, the visual magnitude of this star is diminished by 0.15 from extinction due to interstellar dust.[7]
This is an A-type main-sequence star with a stellar classification of A0 V, per Houk (1979).[3] However, Gray & Garrison (1987) have it classed as B9.5 III-n, suggesting it is a more evolved giant star.[5] HD 119921 is spinning rapidly with a projected rotational velocity of 220 km/s.[9] The star is radiating around 125 times the Sun's luminosity from its photosphere at an effective temperature of 8,801 K.[8]
In 1983, Molaro et al. reported the presence of super-ionized elements (triple-ionized carbon and silicon) in the far ultraviolet spectrum of HD 119921. These anomalous features are not normally detected from a star in this temperature range.[12] Instead, these blue-shifted absorption features may originate in the local interstellar medium.[9]
References
- ↑ 1.0 1.1 1.2 1.3 1.4 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. Gaia DR2 record for this source at VizieR.
- ↑ 2.0 2.1 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 (1979), Michigan catalogue of two-dimensional spectral types for the HD stars, 3, Ann Arbor, Michigan: Dept. of Astronomy, University of Michigan, Bibcode: 1982mcts.book.....H.
- ↑ 4.0 4.1 Eggleton, P. P.; Tokovinin, A. A. (September 2008), "A catalogue of multiplicity among bright stellar systems", Monthly Notices of the Royal Astronomical Society 389 (2): 869–879, doi:10.1111/j.1365-2966.2008.13596.x, Bibcode: 2008MNRAS.389..869E.
- ↑ 5.0 5.1 Gray, R. O.; Garrison, R. F. (December 1987), "The Early A-Type Stars: Refined MK Classification, Confrontation with Stroemgren Photometry, and the Effects of Rotation", Astrophysical Journal Supplement 65: 581, doi:10.1086/191237, Bibcode: 1987ApJS...65..581G.
- ↑ 6.0 6.1 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, doi:10.1051/0004-6361/201219219, A61, Bibcode: 2012A&A...546A..61D.
- ↑ 7.0 7.1 7.2 Gontcharov, G. A. (November 2012), "Spatial distribution and kinematics of OB stars", Astronomy Letters 38 (11): 694–706, doi:10.1134/S1063773712110035, Bibcode: 2012AstL...38..694G.
- ↑ 8.0 8.1 8.2 McDonald, I. et al. (2012), "Fundamental parameters and infrared excesses of Hipparcos stars", Monthly Notices of the Royal Astronomical Society 427 (1): 343–357, doi:10.1111/j.1365-2966.2012.21873.x, Bibcode: 2012MNRAS.427..343M.
- ↑ 9.0 9.1 9.2 Freire Ferrero, R. et al. (February 2012), "High Ionization Species in the Nearby Interstellar Medium from an Exhaustive Analysis of the IUE INES Database", The Astronomical Journal 143 (2): 38, doi:10.1088/0004-6256/143/2/28, 28, Bibcode: 2012AJ....143...28F.
- ↑ "HD 119921". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=HD+119921.
- ↑ Mason, B. D. et al. (2014), "The Washington Visual Double Star Catalog", The Astronomical Journal 122 (6): 3466–3471, doi:10.1086/323920, Bibcode: 2001AJ....122.3466M.
- ↑ Molaro, P.; Morossi, C.; Ramella, M.; Franco, M. (October 1983), "Superionization in the A0 V star HD 119921", Astronomy and Astrophysics 127 (1): L3–L4, Bibcode: 1983A&A...127L...3M.
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