Var 83
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Triangulum |
| Right ascension | 01h 33m 50.02s[1] |
| Declination | +30° 39′ 36.7″[1] |
| Apparent magnitude (V) | 15.4-16.6[2] |
| Characteristics | |
| Spectral type | LBV |
| U−B color index | ~−0.9[2] |
| B−V color index | ~0.1[2] |
| Variable type | LBV |
| Astrometry | |
| Proper motion (μ) | RA: 11.54[3] mas/yr Dec.: -2.75[3] mas/yr |
| Distance | ~3,000,000 ly (~900,000 pc) |
| Absolute magnitude (MV) | −8.4- −9.5[2] |
| Details | |
| Mass | 60[4] M☉ |
| Radius | 150[5] R☉ |
| Luminosity | 2,100,000-4,500,000[5] L☉ |
| Temperature | 18,000-37,000[2][5] K |
| Other designations | |
M33 Var 83, VHK 83, 2MASS J01341090+3034373 | |
| Database references | |
| SIMBAD | data |
VHK 83 (Var 83 in the VHK survey[6]) is a luminous blue variable (LBV) in the constellation Triangulum, in the Triangulum Galaxy. With its bolometric luminosity of at least 2,240,000 times that of the Sun (4,500,000 in some estimates), it was described as "the brightest nonstable star in M33"[6] and is one of the most luminous stars known.
The brightness varies slowly and unpredictably over a 1-2 magnitude visual range and can remain approximately constant for many years. These variations, combined with the high luminosity and temperature of the star, caused it to be grouped with the Hubble-Sandage variables even before the term "Luminous blue variable" was more than a simple description.[7] Despite widespread agreement that it is an LBV, it has yet to be observed in outburst, although the temperature has been observed to change in tandem with the brightness variations.[2]
Temperature estimates for the star range from around 18,000K to well over 30,000K. The hotter temperatures found from fitting the spectral energy distribution (SED) are consistent with the calculated luminosity of an LBV in the quiescent stage, but the spectrum is that of a cooler star.[5]
References
- ^ a b Cutri, Roc M.; Skrutskie, Michael F.; Van Dyk, Schuyler D.; Beichman, Charles A.; Carpenter, John M.; Chester, Thomas; Cambresy, Laurent; Evans, Tracey E.; Fowler, John W.; Gizis, John E.; Howard, Elizabeth V.; Huchra, John P.; Jarrett, Thomas H.; Kopan, Eugene L.; Kirkpatrick, J. Davy; Light, Robert M.; Marsh, Kenneth A.; McCallon, Howard L.; Schneider, Stephen E.; Stiening, Rae; Sykes, Matthew J.; Weinberg, Martin D.; Wheaton, William A.; Wheelock, Sherry L.; Zacarias, N. (2003). "VizieR Online Data Catalog: 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003)". CDS/ADC Collection of Electronic Catalogues. 2246: II/246. Bibcode:2003yCat.2246....0C.
- ^ a b c d e f Humphreys, R. M.; Blaha, C.; d'Odorico, S.; Gull, T. R.; Benvenuti, P. (1984). "IUE and ground-based observations of the Hubble-Sandage variables in M31 and M33". The Astrophysical Journal. 278: 124. Bibcode:1984ApJ...278..124H. doi:10.1086/161774.
- ^ a b Khrutskaya, E. V.; Khovritchev, M. Yu.; Bronnikova, N. M. (2004). "The Pul-3 catalogue of 58483 stars in the Tycho-2 system". Astronomy and Astrophysics. 418: 357–362. Bibcode:2004A&A...418..357K. doi:10.1051/0004-6361:20034232.
- ^ Burggraf, B.; Weis, K.; Bomans, D. J. (2006). "LBVs in M33: Their Environments and Ages". Stellar Evolution at Low Metallicity: Mass Loss. 353: 245. Bibcode:2006ASPC..353..245B.
- ^ a b c d Valeev, A. F.; Sholukhova, O.; Fabrika, S. (2009). "A new luminous variable in M33". Monthly Notices of the Royal Astronomical Society: Letters. 396 (1): L21. arXiv:0903.5222. Bibcode:2009MNRAS.396L..21V. doi:10.1111/j.1745-3933.2009.00654.x. S2CID 14666975.
{{cite journal}}: CS1 maint: unflagged free DOI (link) - ^ a b Van Den Bergh, S.; Herbst, E.; Kowal, C. T. (1975). "A survey of bright variable stars in M33". The Astrophysical Journal Supplement Series. 29: 303. Bibcode:1975ApJS...29..303V. doi:10.1086/190344.
- ^ Humphreys, R. M. (1978). "Luminous variable stars in M31 and M33". The Astrophysical Journal. 219: 445. Bibcode:1978ApJ...219..445H. doi:10.1086/155797.
Further reading
- Van Den Bergh, S; Herbst, E; Kowal, C. T (1975). "A survey of bright variable stars in M33". The Astrophysical Journal Supplement Series. 29: 303. Bibcode:1975ApJS...29..303V. doi:10.1086/190344.
- Corral, L. J (1996). "LBV-Type Stars in M33". The Astronomical Journal. 112: 1450. Bibcode:1996AJ....112.1450C. doi:10.1086/118113.
