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HD 37836
	; A visual band light curve for HD 37836, plotted from ASAS-SN data
Observation data; Epoch J2000 Equinox J2000
Constellation	Dorado
Right ascension	5h 35m 16.633s
Declination	−69° 40′ 38.44″
Apparent magnitude (V)	10.55
Characteristics
Spectral type	B0Iae
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
Distance	163,000 ly ; (49,970 pc)
Absolute magnitude (MV)	−8.5
Details
Radius	85 R☉
Luminosity	4,169,000 L☉
Surface gravity (log g)	2.14 cgs
Temperature	28,200 K
Other designations
	HD 37836, RMC 123, R123, HIP 26222
Database references
SIMBAD	data

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]

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]

References

^ "ASAS-SN Variable Stars Database". ASAS-SN Variable Stars Database. ASAS-SN. Retrieved 6 January 2022.
^ ^a ^b ^c ^d 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.
^ ^a ^b ^c ^d ^e Martin, John C.; Humphreys, Roberta M. (2023-10-30). "A Census of the Most Luminous Stars. I. The Upper HR Diagram for the Large Magellanic Cloud". The Astronomical Journal. 166 (5): 214. Bibcode:2023AJ....166..214M. doi:10.3847/1538-3881/ad011e. ISSN 0004-6256.
^ ^a ^b Lennon, Daniel J.; Marel, Roeland P. van der; Lerate, Mercedes Ramos; O’Mullane, William; Sahlmann, Johannes (2017-07-01). "Gaia TGAS search for Large Magellanic Cloud runaway supergiant stars - Candidate hypervelocity star discovery and the nature of R 71". Astronomy & Astrophysics. 603: A75. arXiv:1611.05504. Bibcode:2017A&A...603A..75L. doi:10.1051/0004-6361/201630076. ISSN 0004-6361. S2CID 119474184.
^ Genderen, A. M. van (2001-02-01). "S Doradus variables in the Galaxy and the Magellanic Clouds". Astronomy & Astrophysics. 366 (2): 508–531. Bibcode:2001A&A...366..508V. doi:10.1051/0004-6361:20000022. ISSN 0004-6361. S2CID 55796300.
^ ^a ^b Richardson, Noel D.; Mehner, Andrea (2018-07-11). "The 2018 Census of Luminous Blue Variables in the Local Group". Research Notes of the AAS. 2 (3): 121. arXiv:1807.04262. Bibcode:2018RNAAS...2..121R. doi:10.3847/2515-5172/aad1f3. ISSN 2515-5172.
^ Pickering, E. C.; Fleming, W. P. (1901-09-01). "Objects having peculiar spectra". The Astrophysical Journal. 14: 144–146. Bibcode:1901ApJ....14..144P. doi:10.1086/140844. ISSN 0004-637X.
^ Smith, Henry J. (1957-04-01). "Spectra of Bright-Line Stars in the Large Magellanic Cloud". Publications of the Astronomical Society of the Pacific. 69 (407): 137. Bibcode:1957PASP...69..137S. doi:10.1086/127032. ISSN 1538-3873. S2CID 122612430.
^ Balona, L A; Handler, G; Chowdhury, S; Ozuyar, D; Engelbrecht, C A; Mirouh, G M; Wade, G A; David-Uraz, A; Cantiello, M (2019-05-21). "Rotational modulation in TESS B stars". Monthly Notices of the Royal Astronomical Society. 485 (3): 3457–3469. arXiv:1902.09470. doi:10.1093/mnras/stz586. ISSN 0035-8711.
^ van Genderen, A. M.; Groot, M.; The, P. S. (1983-01-01). "On the photometric differences between luminous OBA type stars in the LMC with and without P Cygni characteristics". Astronomy and Astrophysics. 117: 53–59. Bibcode:1983A&A...117...53V. ISSN 0004-6361.
^ Stahl, O.; Wolf, B. (1987-07-01). "The peculiar emission-line supergiant HD 37836". Astronomy and Astrophysics. 181: 293–299. Bibcode:1987A&A...181..293S. ISSN 0004-6361.
^ Lortet, M. C. (1988-12-01). "A provisory catalogue of S-Dor candidate stars in the Magellanic Clouds". Bulletin d'Information du Centre de Donnees Stellaires. 35: 145–154. Bibcode:1988BICDS..35..145L. ISSN 1169-8837.
^ van Genderen, A. M.; Sterken, C.; de Groot, M.; Reijns, R. A. (1998-04-01). "Light variations of massive stars (alpha Cyg variables). XV. The LMC supergiants R99 (LBV), R103, R123 (LBV) and R128". Astronomy and Astrophysics. 332: 857–866. Bibcode:1998A&A...332..857V. ISSN 0004-6361.