Bibcode
Evans, C. J.; Kennedy, M. B.; Dufton, P. L.; Howarth, I. D.; Walborn, N. R.; Markova, N.; Clark, J. S.; de Mink, S. E.; de Koter, A.; Dunstall, P. R.; Hénault-Brunet, V.; Maíz Apellániz, J.; McEvoy, C. M.; Sana, H.; Simón-Díaz, S.; Taylor, W. D.; Vink, J. S.
Referencia bibliográfica
Astronomy and Astrophysics, Volume 574, id.A13, 40 pp.
Fecha de publicación:
2
2015
Revista
Número de citas
61
Número de citas referidas
60
Descripción
We present spectral classifications for 438 B-type stars observed as
part of the VLT-FLAMES Tarantula Survey (VFTS) in the 30 Doradus region
of the Large Magellanic Cloud. Radial velocities are provided for 307
apparently single stars, and for 99 targets with radial-velocity
variations which are consistent with them being spectroscopic binaries.
We investigate the spatial distribution of the radial velocities across
the 30 Dor region, and use the results to identify candidate runaway
stars. Excluding potential runaways and members of two older clusters in
the survey region (SL 639 and Hodge 301), we determine a systemic
velocity for 30 Dor of 271.6 ± 12.2 kms-1 from 273
presumed single stars. Employing a 3σ criterion we identify nine
candidate runaway stars (2.9% of the single stars with radial-velocity
estimates). The projected rotational velocities of the candidate
runaways appear to be significantly different to those of the full
B-type sample, with a strong preference for either large (≥345
kms-1) or small (≤65 kms-1) rotational
velocities. Of the candidate runaways, VFTS 358 (classified B0.5: V) has
the largest differential radial velocity (-106.9 ± 16.2
kms-1), and a preliminary atmospheric analysis finds a
significantly enriched nitrogen abundance of 12 + log (N/H) ≳ 8.5.
Combined with a large rotational velocity (vesini = 345
± 22 kms-1), this is suggestive of past binary
interaction for this star.
Table 7 and Appendix A are available in electronic form at http://www.aanda.org
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