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WR 119

WR 119
Observation data
Epoch J2000      Equinox J2000
Constellation Scutum
Right ascension 18h 39m 17.904s[1]
Declination −10° 50′ 30.90″[1]
Apparent magnitude (V) 12.06[2]
Characteristics
Evolutionary stage Wolf-Rayet
Spectral type WC9d[3]
B−V color index +0.93[2]
Astrometry
Proper motion (μ) RA: −1.223[1] mas/yr
Dec.: −5.285[1] mas/yr
Parallax (π)0.2098 ± 0.0155 mas[1]
Distance3,220+1,240
−730[4] pc
Absolute magnitude (MV)−3.91[3]
Details
Mass5.8[3] M☉
Radius3.7[3] R☉
Luminosity50,100[3] L☉
Temperature45,000[3] K
Other designations
WR 119, 2MASS J18391789-1005309
Database references
SIMBADdata

WR 119 is a Wolf–Rayet star located about 10,500 light years away in the constellation Scutum. WR 119 is classified as a WC9 star, belonging to the late-type carbon sequence of Wolf-Rayet stars. WR 119 is noteworthy for being the least luminous known Wolf-Rayet star, at just over 50,000 L☉.[3] The most recent estimate is even lower, at just 42,700 L☉, based on the most recent analysis using Gaia DR2 data.[4]

Properties

WR 119's properties are on the very edge of what may be possible for Wolf-Rayet stars, due to being so extremely dim. Modelling its spectrum using PoWR gives a temperature of 45,000 K. Factoring in the distance used in that study of 3,500 pc, WR 119's luminosity is only 50,100 L☉, derived from Gaia DR2's parallax data. The corresponding radius is only 3.7 R☉, the smallest of the WC9 stars, less than half the size of the average WC9 star. WR 119's luminosity is also just 20% that of the average WC9 star's luminosity. The corresponding mass is just 5.8 M☉, the lowest mass for any Wolf-Rayet star derived using a mass-luminosity relation.[3]

In the visual wavelength, the star is also the dimmest of the WC9 stars (and anything later than WC4 in the study), with a visual luminosity of just 3,130 L☉[3] because most of the 50,100 L☉ is emitted at ultraviolet wavelengths due to WR 119's very high surface temperature.

WR 119 has a strong stellar wind, typical of Wolf-Rayet stars, but weaker than most WC stars. WR 119 loses 10-5.13 M☉ (about 7.41×10−6 M☉) per year because of this stellar wind, which has a terminal velocity of 1,300 kilometres per second. WR 119 also emits a lot of dust, hence the "d" at the end of its spectral type,[3] which may be an indication of binary status.

References

  1. ^ a b c d e Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv:2208.00211. Bibcode:2023A&A...674A...1G. doi:10.1051/0004-6361/202243940. S2CID 244398875. Gaia DR3 record for this source at VizieR.
  2. ^ a b Jayasinghe, T; Kochanek, C S; Stanek, K Z; Shappee, B J; Holoien, T W-S; Thompson, Toda A; Prieto, J L; Dong, Subo; Pawlak, M; Shields, J V; Pojmanski, G; Otero, S; Britt, C A; Will, D (1 July 2018). "The ASAS-SN catalogue of variable stars I: The Serendipitous Survey". Monthly Notices of the Royal Astronomical Society. 477 (3): 3145–3163. arXiv:1803.01001. Bibcode:2018MNRAS.477.3145J. doi:10.1093/mnras/sty838. ISSN 0035-8711.
  3. ^ a b c d e f g h i j Sander, A. A. C.; Hamann, W.-R.; Todt, H.; Hainich, R.; Shenar, T.; Ramachandran, V.; Oskinova, L. M. (2019-01-01). "The Galactic WC and WO stars. The impact of revised distances from Gaia DR2 and their role as massive black hole progenitors". Astronomy and Astrophysics. 621: A92. arXiv:1807.04293. Bibcode:2019A&A...621A..92S. doi:10.1051/0004-6361/201833712. ISSN 0004-6361. S2CID 67754788.
  4. ^ a b Crowther, Paul A.; Rate, Gemma (2020). "Unlocking Galactic Wolf–Rayet stars with Gaia DR2 – I. Distances and absolute magnitudes". Monthly Notices of the Royal Astronomical Society. 493 (1): 1512–1529. arXiv:1912.10125. Bibcode:2020MNRAS.493.1512R. doi:10.1093/mnras/stz3614. S2CID 209444955.
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