|This infobox, "Template:Starbox begin", is from Wikipedia. The list of its authors can be seen in its edit history page. The data in this infobox may not agree or state what Wikipedia states.|
Epoch J2000 Equinox J2000
|Right ascension||01h 00m 55.20s|
|Declination||−71° 37′ 52.9″|
|Apparent magnitude (V)||11.84 - 12.46|
|Evolutionary stage||Red supergiant|
|Spectral type||M0 Iab (K0/1 I - M4.5/5 I)|
|B−V color index||+1.88 - +1.95|
|Radial velocity (Rv)||108.268 km/s|
|Distance||~200,000 ly|
|Absolute magnitude (MV)||−6.5 - −8.4|
|Surface gravity (log g)||−0.2 cgs|
|Surface gravity (log g)||−0.4 cgs|
PMMR 114, LI-SMC 140, 2MASS J01005519-7137529
The spectral type of HV 11423 is variable, from K0-1I in December 2004, to M4I in December 2005, and back to K0-1I by September 2006. Very Large Telescope file spectra show that in December 2001 the star was even cooler (M4-5I). By contrast, in October 1978 and a year later, it appeared as a star of class M0I. The spectral type M4-5 is the latest observed in a supergiant of the Small Magellanic Cloud
HV 11423 is one of largest known stars with an estimated radius over 1,000 times bigger than the sun. It is also a variable star with a variation of up 2 magnitudes at visual wavelengths but essentially constant in the infrared. It is listed in the General Catalogue of Variable Stars as a slow irregular variable, but a period of 720 days has been calculated, as well as a long secondary period of 1,817 days.
The bolometric luminosity is over 300,000 times more than Sun, making it one of most luminous cool supergiants, and appears to have remained unchanged during the brightness and spectral variations. It is thought that the star is currently undergoing a period of intense instability, in which its effective temperature changes from 4,300 to 3,300 K in a time scale of months; V-band variability may be due primarily to variations in temperature as well as changes in the local extinction due to the creation and dissipation of circumstellar dust. It is speculated that the star may be nearing the end of its life.
- Cutri, R. M.; Skrutskie, M. F.; Van Dyk, S.; Beichman, C. A.; Carpenter, J. M.; Chester, T.; Cambresy, L.; Evans, T. et al. (2003). "VizieR Online Data Catalog: 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003)". VizieR On-line Data Catalog: II/246. Originally published in: 2003yCat.2246....0C 2246. Bibcode 2003yCat.2246....0C.
- Levesque, E. M.; Massey, P.; Olsen, K. A. G.; Plez, B. (2009). "The Coolest Stars in the Clouds: Unusual Red Supergiants in the Magellanic Clouds". The Biggest 412: 33. Bibcode 2009ASPC..412...33L.
- Humphreys, R. M. (1979). "M supergiants and the low metal abundances in the Small Magellanic Cloud". Astrophysical Journal 231: 384. Bibcode 1979ApJ...231..384H. doi:10.1086/157201.
- Massey, Philip; Levesque, Emily M.; Olsen, K. A. G.; Plez, Bertrand; Skiff, B. A. (2007). "HV 11423: The Coolest Supergiant in the SMC". The Astrophysical Journal 660: 301. arXiv:astro-ph/0701769. Bibcode 2007ApJ...660..301M. doi:10.1086/513182.
- Samus, N. N.Expression error: Unrecognized word "etal". (2009). "VizieR Online Data Catalog: General Catalogue of Variable Stars (Samus+ 2007-2013)". VizieR On-line Data Catalog: B/gcvs. Originally published in: 2009yCat....102025S 1. Bibcode 2009yCat....102025S.
- Kordopatis, G.; Gilmore, G.; Steinmetz, M.; Boeche, C.; Seabroke, G. M.; Siebert, A.; Zwitter, T.; Binney, J. et al. (2013). "The Radial Velocity Experiment (RAVE): Fourth Data Release". The Astronomical Journal 146 (5): 134. arXiv:1309.4284. Bibcode 2013AJ....146..134K. doi:10.1088/0004-6256/146/5/134.
- Yang, Ming; Jiang, B. W. (2012). "The Period-Luminosity Relation of Red Supergiant Stars in the Small Magellanic Cloud". The Astrophysical Journal 754: 35. arXiv:1205.1275. Bibcode 2012ApJ...754...35Y. doi:10.1088/0004-637X/754/1/35.
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