HD 269810
 An image from the Two Micron All-Sky Survey. HD 269810 is the upper left of the pair of bright stars to the upper right of the nebulosity. | |
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Dorado |
| Right ascension | 05h 35m 13.90s[1] |
| Declination | −67° 33′ 27.5″[1] |
| Apparent magnitude (V) | 12.22[2] |
| Characteristics | |
| Spectral type | O2III(f*)[3] |
| B−V color index | −0.14[2] |
| Astrometry | |
| Radial velocity (Rv) | 303[4] km/s |
| Proper motion (μ) | RA: +1.801[1] mas/yr Dec.: +0.677[1] mas/yr |
| Parallax (π) | −0.0098 ± 0.0310 mas[1] |
| Absolute magnitude (MV) | −6.6[3] |
| Details | |
| Mass | 130[3] M☉ |
| Radius | 18[5] R☉ |
| Luminosity | 2.2 million[3] L☉ |
| Surface gravity (log g) | 4.0[3] cgs |
| Temperature | 52,500[3] K |
| Metallicity | ≤0.1[3] He/H |
| Rotation | 173[6] |
| Other designations | |
| Database references | |
| SIMBAD | data |
HD 269810 is a blue giant star in the Large Magellanic Cloud. It is one of the most massive and most luminous stars known, and one of only a handful of stars with the spectral type O2. The star's name, HD 269810, comes from the Henry Draper Catalogue. The serial number 269810 indicates it was published in the extension of the catalogue and is formally referred to as HDE 269810.
Properties
[edit]HD 269810 is classified as an O2 III (f*) star with a temperature of 52,500 K (52,226.85 °C). The luminosity class of III indicates a star somewhat evolved and expanded compared to the zero-age main sequence. The spectral peculiarity code (f*) indicates strong NIII emission lines, even stronger NNIV emission, and weak HeNII emission. The star's radius is 18 R☉, but because of its high surface temperature it is two million times brighter than the Sun. The high temperature generates a fast stellar wind of 3,750 km/s (2,330 mi/s),[7] shedding over a millionth of the mass of the sun each year.[3] In 1995, HD 269810 was estimated to be 190 times the mass of the Sun[8] and was thought to be the heaviest star known, but its mass estimate is now revised down to be around 130 M☉.[3]
Stars as massive as HD 269810 with metallicity typical of the Large Magellanic Cloud will maintain near-homogeneous chemical structure due to strong convection and rotational mixing. This produces strong helium and nitrogen surface abundance enhancement even during core hydrogen burning. Their rotation rates will also decrease significantly due to mass loss and envelope inflation, so that gamma-ray bursts are unlikely when this type of star reaches core collapse. They are expected to develop directly into Wolf–Rayet stars, passing through WN, WC, and WO stages before exploding as a type Ic supernova and leaving behind a black hole. The total lifetime would be around 2 million years, showing an O-type spectrum for most of that time before a shorter period with a WR spectrum.[9][10]
References
[edit]- ^ a b c d e Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv:2208.00211. Bibcode:2023A&A...674A...1G. doi:10.1051/0004-6361/202243940. S2CID 244398875. Gaia DR3 record for this source at VizieR.
- ^ a b Zacharias, N.; Finch, C. T.; Girard, T. M.; Henden, A.; Bartlett, J. L.; et al. (February 2013). "The Fourth US Naval Observatory CCD Astrograph Catalog (UCAC4)". The Astronomical Journal. 145 (2): 44. arXiv:1212.6182. Bibcode:2013AJ....145...44Z. doi:10.1088/0004-6256/145/2/44. S2CID 119299381.
Zacharias, N.; Finch, C. T.; Girard, T. M.; Henden, A.; Bartlett, J. L.; et al. (July 2012). "VizieR On-line Data Catalog: UCAC4 Catalogue". VizieR On-line Data Catalog: I/322A. 1322. Bibcode:2012yCat.1322....0Z. - ^ a b c d e f g h i Evans, C. J.; Walborn, N. R.; Crowther, P. A.; Hénault-Brunet, V.; Massa, D.; et al. (June 2010). "A Massive Runaway Star from 30 Doradus". The Astrophysical Journal Letters. 715 (2): L74–L79. arXiv:1004.5402. Bibcode:2010ApJ...715L..74E. doi:10.1088/2041-8205/715/2/L74. S2CID 118498849.
- ^ Ardeberg, A.; Brunet, J. P.; Maurice, E.; Prevot, L. (July 1972). "Spectrographic and photometric observations of supergiants and foreground stars in the direction of the Large Magellanic Cloud". Astronomy and Astrophysics Supplement Series. 6: 249. Bibcode:1972A&AS....6..249A.
- ^ Walborn, N. R.; Morrell, N. I.; Howarth, I. D.; Crowther, P. A.; Lennon, D. J.; et al. (June 2004). "A CNO Dichotomy among O2 Giant Spectra in the Magellanic Clouds". The Astrophysical Journal. 608 (2): 1028–1038. arXiv:astro-ph/0403557. Bibcode:2004ApJ...608.1028W. doi:10.1086/420761. S2CID 16656083.
- ^ Penny, L. R.; Sprague, A. J.; Seago, G.; Gies, D. R. (December 2004). "Effects of Metallicity on the Rotational Velocities of Massive Stars". The Astrophysical Journal. 617 (2): 1316–1322. arXiv:astro-ph/0409757. Bibcode:2004ApJ...617.1316P. doi:10.1086/425573. S2CID 14026671.
- ^ Howk, J.C.; Sembach, K.R.; Savage, B.D.; Massa, D.; Friedman, S.D.; Fullerton, A.W. (April 2002). "The global content, distribution, and kinematics of interstellar OVI in the Large Magellanic Cloud". The Astrophysical Journal. 569 (1): 214–232. arXiv:astro-ph/0111566. Bibcode:2002ApJ...569..214H. doi:10.1086/339322. S2CID 9421429.
- ^ Walborn, N.R.; Long, K.S.; Lennon, D.J.; Kudritzki, R.P. (November 1995). "A reconnaissance of the 900–1200 Å spectra of early O stars in the Magellanic Clouds". The Astrophysical Journal Letters. 454: L27. Bibcode:1995ApJ...454L..27W. doi:10.1086/309768. S2CID 121642113.
- ^ Yusof, N.; Hirschi, R.; Meynet, G.; Crowther, P. A.; Ekstrom, S.; et al. (August 2013). "Evolution and fate of very massive stars". Monthly Notices of the Royal Astronomical Society. 433 (2): 1114–1132. arXiv:1305.2099. Bibcode:2013MNRAS.433.1114Y. doi:10.1093/mnras/stt794. S2CID 26170005.
- ^ Köhler, K.; Langer, N.; De Koter, A.; De Mink, S. E.; Crowther, P. A.; et al. (January 2015). "The evolution of rotating very massive stars with LMC composition". Astronomy & Astrophysics. 573: A71. arXiv:1501.03794. Bibcode:2015A&A...573A..71K. doi:10.1051/0004-6361/201424356. S2CID 28962151.
