Star in the Small Magellanic Cloud in the constellation Tucana
HV 11423
HV 11423 is visible in the full-size image, just to the left (south is up) of cluster
NGC 361 (below centre, between the two bright foreground stars). (
Digitized Sky Survey 2)
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.[4]
The bolometric luminosity is about 200,000 times more than
Sun,[8] making it one of the
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,[4] although the mass loss rate is still moderate at 0.0906 M☉ per million years.[8]
References
^
abCutri, 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.
^
abLevesque, 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.
^Samus, N. N.; Durlevich, O. V.; et al. (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.; De Laverny, P.; Recio-Blanco, A.; Williams, M. E. K.; Piffl, T.; Enke, H.; Roeser, S.; Bijaoui, A.; Wyse, R. F. G.; Freeman, K.; Munari, U.; Carrillo, I.; Anguiano, B.; Burton, D.; Campbell, R.; Cass, C. J. P.; Fiegert, K.; Hartley, M.; Parker, Q. A.; Reid, W.; Ritter, A.; Russell, K. S.; 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.
S2CID119221010.