Luminous blue variable star in the constellation Sagittarius
V4650 Sagittarii
V4650 Sgr is the very bright object just off the left edge of this image of the
Quintuplet Cluster, with only its diffraction spikes visible. Credit: HST\NIMCOS (
WFC3)
V4650 Sgr was first catalogued in 1996 as star 362 in a list of stars in the galactic centre region near the
Quintuplet Cluster.[5] The acronym qF is used for stars in the list and so the star name is qF 362. The acronym FMM is also used, hence FMM 362.[6] The LBV nature of qF 362 was not recognised until 1999.[7] It is one of three LBVs close to the Quintuplet Cluster, all highly luminous stars.[8]
V4650 was discovered using
infrared telescopes. It is extremely faint at optical wavelengths due to
interstellar extinction. The
2MASS survey recorded it at 17th magnitude in red light and 19th magnitude in blue light, while it is a 7th magnitude object in
K band infrared.[1]
Properties
V4650 Sgr is calculated to be one of the
most luminous stars known, at 1,700,000 L☉ to 7,943,000 L☉. It is considered to be a bona-fide luminous blue variable, although it has not been observed to change temperature from the S Doradus minimum strip to a cooler outburst state.[9] The infrared brightness has varied between magnitude 7.0 and 7.9.[2] It is calculated to have a temperature of 11,300 K and a radius of 350 R☉. Unlike both the two nearby LBVs, V4650 Sgr has no detectable associated nebulosity.[8]
References
^
abcdefghCutri, 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.
^
abSamus, 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.
^Mauerhan, J. C.; Morris, M. R.; Cotera, A.; Dong, H.; Wang, Q. D.; Stolovy, S. R.; Lang, C.; Glass, I. S. (2010). "Discovery of a Luminous Blue Variable with an Ejection Nebula Near the Quintuplet Cluster". The Astrophysical Journal. 713 (1): L33–L36.
arXiv:1002.3379.
Bibcode:
2010ApJ...713L..33M.
doi:
10.1088/2041-8205/713/1/L33.
S2CID42696538.
^Figer, Donald F.; Morris, Mark; McLean, Ian S. (1996). "Hot Stars in the Quintuplet". The Galactic Center. 102: 263.
Bibcode:
1996ASPC..102..263F.