Astronomy:WBB2016 2

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Short description: Blue supergiant in the constellation Aquila
WBB2016 2
Observation data
Equinox J2000.0]] (ICRS)
Constellation Aquila
Right ascension  19h 10m 21.858s[1]
Declination 09° 05′ 02.53″[1]
Characteristics
Spectral type O2-3.5If*[2]
Astrometry
Distance36,200 ly
(11,100[2] pc)
Details[2]
Mass250±120 (90–240) M
Radius55.41[lower-alpha 1] R
Luminosity4,365,000 L
Temperature35,500 K
Other designations
[WBB2016] 2, 2MASS J19102185+0905025
Database references
SIMBADdata

[WBB2016] 2 is an very massive and luminous star in the H II region Westerhout 49. At a mass of 250 solar masses (although with significant uncertainty) and a luminosity of over 4 million L, it is one of the most massive and most luminous stars known (possibly the most massive), and possibly the most massive one located within our galaxy.[2]

Properties

[WBB2016] 2 is located within the H II region Westerhout 49, about 11.1 kiloparsecs from the Sun. The star is heavily reddened, and it is reddened in the K band by nearly 5 magnitudes, the most of any star in the region. [WBB2016] 2 is classified as an evolved slash star, with a spectral type of O2-3.5If*. The star is one of the most luminous stars known, with a luminosity of 4,365,000 L, and has a temperature of about 35,500 K, corresponding to a radius of over 55 times that of the Sun.[2]

Uncertainties

There is significant uncertainty about [WBB2016] 2's properties. For example, its luminosity may be anywhere between 2,455,000 L and 7,763,000 L. Moreover, there is even greater uncertainty about its mass, which may be anywhere between 110 and 370 M, though it's more likely to be between 90 and 240 M☉.[2]

Notes

  1. Applying the Stefan–Boltzmann law with a nominal solar effective temperature of 5,772 K:
    [math]\displaystyle{ \sqrt{(5772/35,500)^4 * 4,365,000} = 55.41\ R\odot }[/math]

References

  1. 1.0 1.1 Cutri, R. M.; Skrutskie, M. F.; van Dyk, S.; Beichman, C. A.; Carpenter, J. M.; Chester, T.; Cambresy, L.; Evans, T. et al. (2003-06-01). "VizieR Online Data Catalog: 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003)". VizieR Online Data Catalog: II/246. Bibcode2003yCat.2246....0C. 
  2. 2.0 2.1 2.2 2.3 2.4 2.5 Wu, Shi-Wei; Bik, Arjan; Bestenlehner, Joachim M.; Henning, Thomas; Pasquali, Anna; Brandner, Wolfgang; Stolte, Andrea (2016-05-01). "The massive stellar population of W49: A spectroscopic survey". Astronomy and Astrophysics 589: A16. doi:10.1051/0004-6361/201527823. ISSN 0004-6361. Bibcode2016A&A...589A..16W.