Bibcode
Bestenlehner, J. M.; Vink, J. S.; Gräfener, G.; Najarro, F.; Evans, C. J.; Bastian, N.; Bonanos, A. Z.; Bressert, E.; Crowther, P. A.; Doran, E.; Friedrich, K.; Hénault-Brunet, V.; Herrero, A.; de Koter, A.; Langer, N.; Lennon, D. J.; Maíz Apellániz, J.; Sana, H.; Soszynski, I.; Taylor, W. D.
Bibliographical reference
Astronomy and Astrophysics, Volume 530, id.L14
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6
2011
Journal
Citations
103
Refereed citations
84
Description
VFTS 682 is located in an active star-forming region, at a projected
distance of 29 pc from the young massive cluster R136 in the Tarantula
Nebula of the Large Magellanic Cloud. It was previously reported as a
candidate young stellar object, and more recently spectroscopically
revealed as a hydrogen-rich Wolf-Rayet (WN5h) star. Our aim is to obtain
the stellar properties, such as its intrinsic luminosity, and to
investigate the origin of VFTS 682. To this purpose, we model optical
spectra from the VLT-FLAMES Tarantula Survey with the non-LTE stellar
atmosphere code cmfgen, as well as the spectral energy distribution from
complementary optical and infrared photometry. We find the extinction
properties to be highly peculiar (RV ~ 4.7), and obtain a
surprisingly high luminosity log (L/L&sun;) = 6.5 ±
0.2, corresponding to a present-day mass of ~150 M&sun;. The
high effective temperature of 52.2 ± 2.5 kK might be explained by
chemically homogeneous evolution - suggested to be the key process in
the path towards long gamma-ray bursts. Lightcurves of the object show
variability at the 10% level on a timescale of years. Such changes are
unprecedented for classical Wolf-Rayet stars, and are more reminiscent
of Luminous Blue Variables. Finally, we discuss two possibilities for
the origin of VFTS 682: (i) the star either formed in situ, which would
have profound implications for the formation mechanism of massive stars,
or (ii) VFTS 682 is a slow runaway star that originated from the dense
cluster R136, which would make it the mostmassive runaway known to date.
Based on observations at the European Southern Observatory Very Large
Telescope in programme 182.D-0222.
Related projects
Physical properties and evolution of Massive Stars
This project aims at the searching, observation and analysis of massive stars in nearby galaxies to provide a solid empirical ground to understand their physical properties as a function of those key parameters that gobern their evolution (i.e. mass, spin, metallicity, mass loss, and binary interaction). Massive stars are central objects to
Sergio
Simón Díaz