HD 37836

HD 37836 is a candidate luminous blue variable located in the Large Magellanic Cloud and one of the brightest stars in its galaxy.^[4][6]

HD 37836

A visual band light curve for HD 37836, plotted from ASAS-SN data[1]
Observation data Epoch J2000      Equinox J2000
Constellation	Dorado
Right ascension	5h 35m 16.633s[2]
Declination	−69° 40′ 38.44″[2]
Apparent magnitude (V)	10.55[3]
Characteristics
Spectral type	B0Iae[4]
Apparent magnitude (U)	9.87
Apparent magnitude (B)	10.736
Apparent magnitude (R)	10.73
Apparent magnitude (I)	10.164
Apparent magnitude (J)	9.886
Apparent magnitude (H)	9.72
Apparent magnitude (K)	9.381
Variable type	cLBV and α Cygni
Astrometry
Radial velocity (Rv)	−474.41 km/s
Parallax (π)	0.0271±0.0139 mas[2]
Distance	163,000 ly (49,970 pc)
Absolute magnitude (MV)	−8.5[5]
Details
Radius	85[3] R☉
Luminosity	4,169,000[3] L☉
Surface gravity (log g)	2.14[2] cgs
Temperature	28,200[3] K
Other designations
HD 37836, RMC 123, R123, HIP 26222
Database references
SIMBAD	data

History

The star was first mentioned in a 1901 paper as an object with an unusual spectrum with bright H-alpha, H-beta and H-delta lines located in the LMC.^[7] Later it was catalogued in the Henry Draper Catalogue and given the designation HD 37836. In 1957 it was noted that its spectral lines show a P Cygni profile.^[8]

Stellar properties

HD 37836 is an extremely luminous blue supergiant with parameters similar to other similar stars, such as η Carinae A. It is also an α Cygni variable.^[9] Its apparent magnitude varies by ~0.2 magnitudes.

In 1983, its luminosity was estimated to be 5.6 million L_☉ and its mass was estimated to be 100 M_☉, which would make it one of the most luminous and most massive known stars.^[10]

A paper published in 1987 again noted the star's peculiar spectrum. It also concluded that the star might be similar to HD 269445 and Hen S 131. The star's luminosity was estimated to be around 4 million L_☉.^[11]

A year later, it was classified as a possible S Doradus variable.^[12] A 1998 paper considers it an active LBV, an Alpha Cygni variable, and a 2018 census of LBVs considers it to be a candidate.^[6][13]

A 2023 paper estimates its luminosity to be 4.2 million solar luminosities and its temperature to be 28,200 K based on the star's spectral type, corresponding to a radius of 85 solar radii, comparable to that of Rigel.^[3]