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)
Observation data
Epoch J2000      Equinox J2000
Constellation Sagittarius
Right ascension 17h 46m 17.982s[1]
Declination −28° 49′ 03.46″[1]
Characteristics
Evolutionary stage LBV
Apparent magnitude (B) 19.3[1]
Apparent magnitude (R) 16.4[1]
Apparent magnitude (J) 12.310[1]
Apparent magnitude (H) 8.970[1]
Apparent magnitude (K) 7.090[1]
Variable type LBV[2]
Astrometry
Distance8,000[3] pc
Details[3]
Mass46 M☉
Radius350 R☉
Luminosity1,770,000 - 7,943,000[4] L☉
Temperature11,300 K
Other designations
V4650 Sagittarii, qF 362, 2MASS J17461798-2849034, SSTGC 629806
Database references
SIMBADdata

V4650 Sagittarii (qF362) is a luminous blue variable star (LBV) in the constellation of Sagittarius. Located some 25,000 light years away, the star is positioned on the edge of a starburst cluster known as the Quintuplet cluster.

Discovery

Quintuplet cluster region, with V4650 Sgr to the left of the Pistol Nebula (annotated in full-size image)

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

A near-infrared (K band) light curve for V4650 Sagittarii, adapted from Glass et al. (1999)[6]

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

  1. ^ a b c d e f g h 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.
  2. ^ a b 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.
  3. ^ a b Najarro, F.; Figer, D. F.; Hillier, D. J.; Geballe, T. R.; Kudritzki, R. P. (2009). "Metallicity in the Galactic Center: The Quintuplet Cluster". The Astrophysical Journal. 691 (2): 1816–1827. arXiv:0809.3185. Bibcode:2009ApJ...691.1816N. doi:10.1088/0004-637X/691/2/1816. S2CID 15473563.
  4. ^ 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. S2CID 42696538.
  5. ^ Figer, Donald F.; Morris, Mark; McLean, Ian S. (1996). "Hot Stars in the Quintuplet". The Galactic Center. 102: 263. Bibcode:1996ASPC..102..263F.
  6. ^ a b Glass, I. S.; Matsumoto, S.; Carter, B. S.; Sekiguchi, K. (1999). "Luminous variables in the Quintuplet cluster". Monthly Notices of the Royal Astronomical Society. 304 (1): L10–L14. Bibcode:1999MNRAS.304L..10G. doi:10.1046/j.1365-8711.1999.02454.x.
  7. ^ Figer, Donald F.; McLean, Ian S.; Morris, Mark (1999). "Massive Stars in the Quintuplet Cluster". The Astrophysical Journal. 514 (1): 202–220. arXiv:astro-ph/9903281. Bibcode:1999ApJ...514..202F. doi:10.1086/306931. S2CID 15816020.
  8. ^ a b Lau, R. M.; Herter, T. L.; Morris, M. R.; Adams, J. D. (2014). "Nature versus Nurture: Luminous Blue Variable Nebulae in and near Massive Stellar Clusters at the Galactic Center". The Astrophysical Journal. 785 (2): 120. arXiv:1403.5298. Bibcode:2014ApJ...785..120L. doi:10.1088/0004-637X/785/2/120. S2CID 118447462.
  9. ^ Nazé, Y.; Rauw, G.; Hutsemékers, D. (2012). "The first X-ray survey of Galactic luminous blue variables". Astronomy & Astrophysics. 538: A47. arXiv:1111.6375. Bibcode:2012A&A...538A..47N. doi:10.1051/0004-6361/201118040. S2CID 43688343.
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