V4650 Sagittarii

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V4650 Sagittarii
Uncovering the secrets of the Quintuplet Cluster.jpg
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
Distance 8,000 [3]   pc
Details [3]
Mass 46  M
Radius 350  R
Luminosity 1,770,000  L
Temperature 11,300  K
Other designations
V4650  Sagittarii, qF  362, 2MASS  J17461798-2849034, SSTGC  629806
Database references
SIMBAD data

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.

Contents

Discovery

Quintuplet cluster region, with V4650 Sgr to the left of the Pistol Nebula (annotated in full-size image) Quintuplet cluster region (1002.3379).jpg
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. [4] 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. [5] The LBV nature of qF 362 was not recognised until 1999. [6] It is one of three LBVs close to the Quintuplet Cluster, all highly luminous stars. [7]

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) V4650SgrLightCurve.png
A near-infrared (K band) light curve for V4650 Sagittarii, adapted from Glass et al. (1999)

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. [8] 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. [7]

Related Research Articles

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<span class="mw-page-title-main">V4998 Sagittarii</span> Luminous blue variable star in the constellation Sagittarius

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<span class="mw-page-title-main">T Persei</span> Star in the constellation Perseus

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<span class="mw-page-title-main">HD 316285</span> Star in the constellation Sagittarius

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<span class="mw-page-title-main">V915 Scorpii</span> Variable star in the constellation Scorpius

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<span class="mw-page-title-main">V1936 Aquilae</span> Blue supergiant star in the constellation Aquila

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References

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  7. 1 2 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.
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