Location of HD 93205 (circled), southwest of Eta Carinae, the brightest star in the image | |
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Carina |
| Right ascension | 10 44 33.739 |
| Declination | −59° 44′ 15.43″ |
| Apparent magnitude (V) | 7.75 |
| Characteristics | |
| Spectral type | O3.5Vf + O8V |
| U−B color index | −0.91 |
| B−V color index | +0.05 |
| Variable type | Ellipsoidal |
| Astrometry | |
| Radial velocity (Rv) | 3.6 km/s |
| Proper motion (μ) | RA: −6.619 mas/yr Dec.: 2.947 mas/yr |
| Parallax (π) | 0.4308 ± 0.0248 mas |
| Distance | 7,600 ± 400 ly (2,300 ± 100 pc) |
| Absolute magnitude (MV) | −5.87 + −4.32 |
| Orbit | |
| Period (P) | 6.0803 days |
| Eccentricity (e) | 0.370 |
| Inclination (i) | 60° |
| Semi-amplitude (K1) (primary) | 132.6 km/s |
| Semi-amplitude (K2) (secondary) | 313.6 km/s |
| Details | |
| Mass | 40 - 60 M☉ |
| Radius | 9.2 R☉ |
| Luminosity | 1,160,000 L☉ |
| Temperature | 51,300 K |
| secondary | |
| Mass | 17 - 25.3 M☉ |
| Radius | 7.0 R☉ |
| Luminosity | 112,000 L☉ |
| Temperature | 38,000 K |
| Age | < 2 Myr |
| Other designations | |
| V560 Car, CD−59°3294, HD 93205, SAO 238418 | |
| Database references | |
| SIMBAD | data |
HD 93205, or V560 Carinae, is a binary stellar system, in the Carina Nebula (NGC 3372) in the constellation Carina. It consists of two massive O-stars that revolve around each other in 6 days.
The more massive member of the pair is an O3.5 main sequence star. The spectrum shows some ionised nitrogen and helium emission lines, indicating some mixing of fusion products to the surface and a strong stellar wind. The mass calculated from apsidal motion of the orbits is 40 to 60 M☉. This is somewhat lower than expected from evolutionary modelling of a star with its observed parameters.
The less massive member is an O8 main sequence star of approximately 20 M☉. It moves in its orbit at a speed of over 300 km/s and is considered to be a relativistic binary, which causes the apses of the orbit to change in a predictable way.
In 1985, Arnout van Genderen et al. reported that the star appeared to be "variable in brightness". Eleonora A. Antokhina et al. confirmed the star's variability in the year 2000, and presented an extensive analysis of the light curve. The star was given its variable star designation, V560 Carinae, in 2001. The closeness of the two stars causes them to become deformed, and this means that the observed brightness of the system varies slightly every six days during its orbit. The total amplitude of the variation is only 0.02 magnitudes.
It is generally considered as a member of the open cluster Trumpler 16. Among its neighbors are some of the most massive and luminous stars in the galaxy, like Eta Carinae, HD 93250 and the binary WR 25. It lies five arc-minutes from Eta Carinae.
References
- ^ Brown, A. G. A.; et al. (Gaia collaboration) (2021). "Gaia Early Data Release 3: Summary of the contents and survey properties". Astronomy & Astrophysics. 649: A1. arXiv:2012.01533. Bibcode:2021A&A...649A...1G. doi:10.1051/0004-6361/202039657. S2CID 227254300. (Erratum: doi:10.1051/0004-6361/202039657e). Gaia EDR3 record for this source at VizieR.
- ^ Ducati, J. R. (2002). "VizieR Online Data Catalog: Catalogue of Stellar Photometry in Johnson's 11-color system". CDS/ADC Collection of Electronic Catalogues. 2237. Bibcode:2002yCat.2237....0D.
- Sota, A.; Maíz Apellániz, J.; Morrell, N. I.; Barbá, R. H.; Walborn, N. R.; Gamen, R. C.; Arias, J. I.; Alfaro, E. J. (2014). "The Galactic O-Star Spectroscopic Survey (GOSSS). II. Bright Southern Stars". The Astrophysical Journal Supplement Series. 211 (1): 84. arXiv:1312.6222. Bibcode:2014ApJS..211...10S. doi:10.1088/0067-0049/211/1/10. S2CID 118847528. 10.
- ^ 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.
- ^ Morrell, N. I.; Barbá, R. H.; Niemela, V. S.; Corti, M. A.; Albacete Colombo, J. F.; Rauw, G.; Corcoran, M.; Morel, T.; Bertrand, J.-F.; Moffat, A. F. J.; St-Louis, N. (2001). "Optical spectroscopy of X-Mega targets - II. The massive double-lined O-type binary HD 93205". Monthly Notices of the Royal Astronomical Society. 326 (1): 85–94. arXiv:astro-ph/0105014. Bibcode:2001MNRAS.326...85M. doi:10.1046/j.1365-8711.2001.04500.x. S2CID 16221731.
- ^ Benvenuto, O. G.; Serenelli, A. M.; Althaus, L. G.; Barbá, R. H.; Morrell, N. I. (2002). "Calculation of the masses of the binary star HD 93205 by application of the theory of apsidal motion". Monthly Notices of the Royal Astronomical Society. 330 (2): 435–442. arXiv:astro-ph/0110662. Bibcode:2002MNRAS.330..435B. doi:10.1046/j.1365-8711.2002.05083.x. S2CID 16834579.
- ^ Antokhina; et al. (2000). "Light Curve Solution of HD 93205 (O3 V + O8 V) Containing the Earliest Known Star in a Well-studied Binary". The Astrophysical Journal. 529 (1): 463–476. Bibcode:2000ApJ...529..463A. doi:10.1086/308228. S2CID 117107602.
- "Hipparcos Tools Interactive Data Access". Hipparcos. ESA. Retrieved 8 December 2021.
- van Genderen, A. M.; Alphenaar, P.; van der Bij, M. D. P.; Deul, E. R.; van Driel, W.; van Heerde, G. M.; de Lange, L.; van Leeuwen, F.; Meys, J. J. M.; Oppe, J.; The, P. S.; Wiertz, M. J. J. (August 1985). "An investigation of the micro-variations of highly luminous OBA type stars .I". Astronomy and Astrophysics, Suppl. Ser. 61: 213–220. Bibcode:1985A&AS...61..213V. Retrieved 11 January 2025.
- Kazarovets, E. V.; Samus, N. N.; Durlevich, O. V. (July 2001). "The 76th Name-List of Variable Stars" (PDF). Information Bulletin on Variable Stars. 5135: 1–67. Bibcode:2001IBVS.5135....1K. Retrieved 11 January 2025.
- Shull, J. Michael; Darling, Jeremy; Danforth, Charles W. (2021). "Gaia EDR3 Parallax Distances to the Great Carina Nebula and Its Star Clusters (Trumpler 14, 15, 16)". The Astrophysical Journal. 914 (1): 18. arXiv:2103.07922. Bibcode:2021ApJ...914...18S. doi:10.3847/1538-4357/abf4d8. S2CID 232233703.
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