The VLT-FLAMES survey of massive stars: atmospheric parameters and rotational velocity distributions for B-type stars in the Magellanic Clouds ,

By I. Hunter, D. Lennon, P. Dufton, C. Trundle, S. Simón-Díaz, S. Smartt, R. Ryans, Christopher H. Evans. 2007

148 citations recorded by the source corpus.

Aims. We aim to provide the atmospheric parameters and rotational velocities for a large sample of O- and early B-type stars, analysed in a homogeneous and consistent manner, for use in constraining theoretical models. Methods. Atmospheric parameters, stellar masses, and rotational velocities have been estimated for approximately 250 early B-type stars in the Large (LMC) and Small (SMC) Magellanic Clouds from high-resolution VLT-FLAMES data using the non-LTE TLUSTY model atmosphere code. This data set has been supplemented with our previous analyses of some 50 0-type stars (Mokiem et al. 2006, 2007) and 100 narrow-lined early B-type stars (Hunter et al. 2006; Trundle et al. 2007) from the same survey, providing a sample of ∼400 early-type objects. Results. Comparison of the rotational velocities with evolutionary tracks suggests that the end of core hydrogen burning occurs later than currently predicted and we argue for an extension of the evolutionary tracks. We also show that the large number of the luminous blue supergiants observed in the fields are unlikely to have directly evolved from main-sequence massive 0-type stars as neither their low rotational velocities nor their position on the H-R diagram are predicted. We suggest that blue loops or mass-transfer binary systems may populate the blue supergiant regime. By comparing the rotational velocity distributions of the Magellanic Cloud stars to a similar Galactic sample, we find that (at 3σ confidence level) massive stars (above 8 M ⊙ ) in the SMC rotate faster than those in the solar neighbourhood. However there appears to be no significant difference between the rotational velocity distributions in the Galaxy and the LMC. We find that the υ sin i distributions in the SMC and LMC can modelled with an intrinsic rotational velocity distribution that is a Gaussian peaking at 175 km s -1 (SMC) and 100 km s -1 (LMC) with a 1/e half width of 150 km s -1 . We find that in NGC 346 in the SMC, the 10-25 M ⊙ main-sequence stars appear to rotate faster than their higher mass counterparts. It is not expected that 0-type stars spin down significantly through angular momentum loss via stellar winds at SMC metallicity, hence this could be a reflection of mass dependent birth spin rates. Recently Yoon et al. (2006) have determined rates of GRBs by modelling rapidly rotating massive star progenitors. Our measured rotational velocity distribution for the 10-25 M ⊙ stars is peaked at slightly higher velocities than they assume, supporting the idea that GRBs could come from rapid rotators with initial masses as low as 14 M ⊙ at low metallicities.

Subfields: Astronomy and Astrophysics, Instrumentation

View Paper: https://www.semanticscholar.org/paper/7b140e03f43b26a98a855ea09fc62108ef3225aa

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In Astronomy and Astrophysics

1. Selma de Mink
2. S. Smartt
3. N. Langer
4. M. Limongi
5. A. Chieffi
6. A. D. Koter
7. Stan Woosley
8. Matteo Cantiello

In Instrumentation

1. Selma de Mink
2. N. Langer
3. A. Chieffi
4. M. Limongi
5. A. D. Koter
6. S. Smartt
7. J. Brinchmann
8. D. Lennon

Citations in the corpus

• The VLT FLAMES Survey of Massive Stars: Rotation and Nitrogen Enrichment as the Key to Understanding Massive Star Evolution (2007, background): “Hunter et al. (2007) and Trundle et al. (2007) (hereafter Papers I and II, respectively) have presented chemical abundances for the narrow-lined objects (predominately slow rotators) in the LMC sample.”
• Galaxies with Wolf-Rayet signatures in the low-redshift Universe. A survey using the Sloan Digital Sky Survey (2008, background): “While there could also be a contribution from OB stars, given their observed elevated surfaced abundance (e.g. Hunter et al. 2008, 2007), it is not clear that this would cause a systematic offset at low EW(Hβ).”
• The death of massive stars – I. Observational constraints on the progenitors of Type II-P supernovae (2008, methodology): “The Geneva rotating stellar evolution models have come very close (Ekström et al. 2012), but assume a single initial rotational velocity rather than a distribution of rotation velocities as are observed (Hunter et al. 2008).”
• PRE-SUPERNOVA EVOLUTION OF ROTATING SOLAR METALLICITY STARS IN THE MASS RANGE 13–120 M☉ AND THEIR EXPLOSIVE YIELDS (2012, background): “…Program, a series of papers came out over the years presenting a large database of stars for which a quite detailed surface chemical abundances and projected rotational velocities (v sin(i)) are now available (Hunter et al. 2007; Trundle et al. 2007; Hunter et al. 2008, 2009; Dunstall et al. 2011).”
• Sub-surface convection zones in hot massive stars and their observable consequences (2009, methodology): “7, we show the microturbulent velocities for the LMC stars of Hunter et al. (2008b) versus the stellar surface gravity.”
• The Effect of Stellar Rotation on Colour-Magnitude Diagrams: On the apparent presence of multiple populations in intermediate age stellar clusters (2009, background): “Models of cluster CMDs that include rotation can explain the spread observed near the turn-off of intermediate age clusters in the LMC (Mackey & Broby Nielsen 2007; Milone et al. 2009; Goudfrooij et al. 2009).”
• Presupernova Evolution and Explosive Nucleosynthesis of Rotating Massive Stars in the Metallicity Range −3 ≤ [Fe/H] ≤ 0 (2018, methodology): “The number of core H-burning stars (log g 3.2), for which the determination of both the surface N abundance and v sin (i) is available, is 62 and 30 for NGC 2004 and N11, respectively.”