HD 269810

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.

HD 269810

Observation data Epoch J2000      Equinox J2000
Constellation	Dorado
Right ascension	05^h 35^m 13.9^s
Declination	−67° 33′ 27.5″
Apparent magnitude (V)	12.22[1]
Characteristics
Spectral type	O2III(f^*)[2]
B−V color index	−0.14[1]
Variable type	None
Astrometry
Radial velocity (Rv)	303[3] km/s
Proper motion (μ)	RA: 0.9[4] mas/yr Dec.: -0.9[4] mas/yr
Absolute magnitude (MV)	−6.6[2]
Details
Mass	130[2] M☉
Radius	18[5] R☉
Luminosity	2.2 million[2] L☉
Surface gravity (log g)	4.0[2] cgs
Temperature	52,500[2] K
Metallicity	≤0.1[2] He/H
Rotation	173[6]
Other designations
GCRV 24403, RMC 122, UBV 5767, ARDB C54, SK -67° 211, UCAC2 2218036, ARDB 317, GSC 09162-00101, TYC 9162-101-1, CSI-67-05351, 2MASS J05351389-6733275, UBV M 28781
Database references
SIMBAD	data

Name

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.

Details

HD 269810 is classified as an O2III(f^*) star with a temperature of 52,500 K (52,200 °C; 94,000 °F). 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 N_III emission lines, even stronger NN_IV emission, and weak HeN_II 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.[2] 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 the mass is now thought to be around 130 M_☉.[2]

Evolution

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

1. 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.
   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.
2. 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.
3. 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.
4. Høg, E.; Fabricius, C.; Makarov, V. V.; Urban, S.; Corbin, T.; et al. (March 2000). "The Tycho-2 catalogue of the 2.5 million brightest stars". Astronomy and Astrophysics. 355: L27–L30. Bibcode:2000A&A...355L..27H. doi:10.1888/0333750888/2862.
5. 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.
6. 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.
7. Howk, J. C.; Sembach, K. R.; Savage, B. D.; Massa, D.; Friedman, S. D.; et al. (April 2002). "The Global Content, Distribution, and Kinematics of Interstellar Oviin the Large Magellanic Cloud". The Astrophysical Journal. 569 (1): 214–232. arXiv:astro-ph/0111566. Bibcode:2002ApJ...569..214H. doi:10.1086/339322.
8. 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.
9. 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.
10. 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.

External links

• Heaviest Known Star Observed from Space