S Doradus

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S Doradus
Observation data
Epoch J2000      Equinox J2000
Constellation Dorado
Right ascension 05h 18m 14.35s[1]
Declination −69° 15′ 01.10″[1]
Apparent magnitude (V) 9.565[1] (8.6 to 11.5 (B))[2]
Spectral type LBV
U−B color index –0.98[3]
B−V color index +0.11[3]
Variable type LBV
Radial velocity (Rv) +228[4] km/s
Proper motion (μ) RA: 0.7[1] mas/yr
Dec.: 4.9[1] mas/yr
Distance 169,000 ly
(51,800 pc)
Absolute magnitude (MV) –9.9
Mass 45[5] M
Radius 100–380[5] R
Luminosity 1.0 × 106[5] L
Temperature 9–20,000[5] K
Other designations
CD-69 295, HD 35343, CPD-69 356, IRAS 05182-6918, AAVSO 0518-69.
Database references

S Doradus is one of the brightest stars in the Large Magellanic Cloud,[6] a satellite of the Milky Way. A hypergiant, it is one of the most luminous stars known (sometimes more luminous than −10 absolute magnitude), but so far away that it is invisible to the naked eye.

This star belongs to its own eponymous S Doradus class of variable stars (these classes are usually named after their prototypes); also designated as the class luminous blue variable or LBV, of which S Doradus forms the archetype. S Doradus exhibits long, slow changes in brightness, punctuated by occasional outbursts. The spectrum is variable, a typical and defining characteristic of LBVs. In its quiescent phase, it has a B type spectrum (with emission) and a temperature around 20,000K. In outburst the temperature decreases and has been observed with the spectrum of an F supergiant and a temperature below 8,000K.[6]

S Doradus is the brightest member of the open cluster NGC 1910, visible in binoculars as a bright condensation within the main bar of the LMC.


  1. ^ a b c d e Høg, E. 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 
  2. ^ "S Dor", General Catalogue of Variable Stars (Sternberg Astronomical Institute, Moscow, Russia), retrieved 2010-11-24 
  3. ^ a b Nicolet, B. (1978), "Photoelectric photometric Catalogue of homogeneous measurements in the UBV System", Astronomy and Astrophysics Supplement Series 34: 1–49, Bibcode:1978A&AS...34....1N 
  4. ^ Evans, D. S. (June 20–24, 1966). "The Revision of the General Catalogue of Radial Velocities". In Batten, Alan Henry; Heard, John Frederick. Determination of Radial Velocities and their Applications, Proceedings from IAU Symposium no. 30. University of Toronto: International Astronomical Union. Bibcode:1967IAUS...30...57E. 
  5. ^ a b c d Lamers, H. J. G. L. M. (February 6–10, 1995), "Observations and Interpretation of Luminous Blue Variables", Proceedings of IAU Colloquium 155, Astrophysical applications of stellar pulsation, Cape Town, South Africa: Astronomical Society of the Pacific, pp. 176–191, Bibcode:1995ASPC...83..176L 
  6. ^ a b Massey, Philip (February 2000), "An Unprecedented Change in the Spectrum of S Doradus: As Cool as It Gets", The Publications of the Astronomical Society of the Pacific 112 (768): 144–147, Bibcode:2000PASP..112..144M, doi:10.1086/316515 

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