Abstract
We present an analysis of high-resolution FLAMES spectra of approximately 50 early B-type stars in three young clusters at different metallicities, NGC6611 in the Galaxy, N 11 in the Large Magellanic Cloud (LMC) and NGC 346 in the Small Magellanic Cloud (SMC). Using the TLUSTY non-LTE model atmospheres code, atmospheric parameters and photospheric abundances (C, N, O, Mg and Si) of each star have been determined. These results represent a significant improvement on the number of Magellanic Cloud B-type stars with detailed and homogeneous estimates of their atmospheric parameters and chemical compositions. The relationships between effective temperature and spectral type are discussed for all three metallicity regimes, with the effective temperature for a given spectral type increasing as one moves to a lower metallicity regime. Additionally the difficulties in estimating the microturbulent velocity and the anomalous values obtained, particularly in the lowest metallicity regime, are discussed. Our chemical composition estimates are compared with previous studies, both stellar and interstellar with, in general, encouraging agreement being found. Abundances in the Magellanic Clouds relative to the Galaxy are discussed and we also present our best estimates of the base-line chemical composition of the LMC and SMC as derived from B-type stars. Additionally we discuss the use of nitrogen as a probe of the evolutionary history of stars, investigating the roles of rotational mixing, mass-loss, blue loops and binarity on the observed nitrogen abundances and making comparisons with stellar evolutionary models where possible.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 277-300 |
| Number of pages | 24 |
| Journal | Astronomy and Astrophysics |
| Volume | 466 |
| Issue number | 1 |
| DOIs | |
| State | Published - Apr 2007 |
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Keywords
- Galaxies: abundances
- Magellanic clouds
- Stars: abundances
- Stars: atmospheres
- Stars: early-type
ASJC Scopus subject areas
- Space and Planetary Science
Cite this
The VLT-FLAMES survey of massive stars : Surface chemical compositions of B-type stars in the Magellanic Clouds. / Hunter, I.; Dufton, P. L.; Smartt, S. J.; Ryans, R. S I; Evans, C. J.; Lennon, D. J.; Trundle, C.; Hubeny, Ivan -; Lanz, T.
In: Astronomy and Astrophysics, Vol. 466, No. 1, 04.2007, p. 277-300.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - The VLT-FLAMES survey of massive stars
T2 - Surface chemical compositions of B-type stars in the Magellanic Clouds
AU - Hunter, I.
AU - Dufton, P. L.
AU - Smartt, S. J.
AU - Ryans, R. S I
AU - Evans, C. J.
AU - Lennon, D. J.
AU - Trundle, C.
AU - Hubeny, Ivan -
AU - Lanz, T.
PY - 2007/4
Y1 - 2007/4
N2 - We present an analysis of high-resolution FLAMES spectra of approximately 50 early B-type stars in three young clusters at different metallicities, NGC6611 in the Galaxy, N 11 in the Large Magellanic Cloud (LMC) and NGC 346 in the Small Magellanic Cloud (SMC). Using the TLUSTY non-LTE model atmospheres code, atmospheric parameters and photospheric abundances (C, N, O, Mg and Si) of each star have been determined. These results represent a significant improvement on the number of Magellanic Cloud B-type stars with detailed and homogeneous estimates of their atmospheric parameters and chemical compositions. The relationships between effective temperature and spectral type are discussed for all three metallicity regimes, with the effective temperature for a given spectral type increasing as one moves to a lower metallicity regime. Additionally the difficulties in estimating the microturbulent velocity and the anomalous values obtained, particularly in the lowest metallicity regime, are discussed. Our chemical composition estimates are compared with previous studies, both stellar and interstellar with, in general, encouraging agreement being found. Abundances in the Magellanic Clouds relative to the Galaxy are discussed and we also present our best estimates of the base-line chemical composition of the LMC and SMC as derived from B-type stars. Additionally we discuss the use of nitrogen as a probe of the evolutionary history of stars, investigating the roles of rotational mixing, mass-loss, blue loops and binarity on the observed nitrogen abundances and making comparisons with stellar evolutionary models where possible.
AB - We present an analysis of high-resolution FLAMES spectra of approximately 50 early B-type stars in three young clusters at different metallicities, NGC6611 in the Galaxy, N 11 in the Large Magellanic Cloud (LMC) and NGC 346 in the Small Magellanic Cloud (SMC). Using the TLUSTY non-LTE model atmospheres code, atmospheric parameters and photospheric abundances (C, N, O, Mg and Si) of each star have been determined. These results represent a significant improvement on the number of Magellanic Cloud B-type stars with detailed and homogeneous estimates of their atmospheric parameters and chemical compositions. The relationships between effective temperature and spectral type are discussed for all three metallicity regimes, with the effective temperature for a given spectral type increasing as one moves to a lower metallicity regime. Additionally the difficulties in estimating the microturbulent velocity and the anomalous values obtained, particularly in the lowest metallicity regime, are discussed. Our chemical composition estimates are compared with previous studies, both stellar and interstellar with, in general, encouraging agreement being found. Abundances in the Magellanic Clouds relative to the Galaxy are discussed and we also present our best estimates of the base-line chemical composition of the LMC and SMC as derived from B-type stars. Additionally we discuss the use of nitrogen as a probe of the evolutionary history of stars, investigating the roles of rotational mixing, mass-loss, blue loops and binarity on the observed nitrogen abundances and making comparisons with stellar evolutionary models where possible.
KW - Galaxies: abundances
KW - Magellanic clouds
KW - Stars: abundances
KW - Stars: atmospheres
KW - Stars: early-type
UR - http://www.scopus.com/inward/record.url?scp=34249286508&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=34249286508&partnerID=8YFLogxK
U2 - 10.1051/0004-6361:20066148
DO - 10.1051/0004-6361:20066148
M3 - Article
AN - SCOPUS:34249286508
VL - 466
SP - 277
EP - 300
JO - Astronomy and Astrophysics
JF - Astronomy and Astrophysics
SN - 0004-6361
IS - 1
ER -