|
| | | | |
| | | |
| Stat |
Members: 3645
Articles: 2'500'096
Articles rated: 2609
19 April 2024 |
|
| | | | |
|
Article overview
| |
|
|
The VLT-FLAMES Tarantula Survey XIX. B-type Supergiants - Atmospheric Parameters and Nitrogen Abundances to Investigate the Role of Binarity and the Width of the Main Sequence | | C. M. McEvoy
; P. L. Dufton
; C. J. Evans
; V. M. Kalari
; N. Markova
; S. Simón-Díaz
; J. S. Vink
; N. R. Walborn
; P. A. Crowther
; A. de Koter
; S. E. de Mink
; P. R. Dunstall
; V. Hénault-Brunet
; A. Herrero
; N. Langer
; D. J. Lennon
; J. Maíz Apellániz
; F. Najarro
; J. Puls
; H. Sana
; F. R. N. Schneider
; W. D. Taylor
; | | Date: |
8 Dec 2014 | | Abstract: | TLUSTY non-LTE model atmosphere calculations have been used to determine
atmospheric parameters and nitrogen (N) abundances for 34 single and 18 binary
B-type supergiants (BSGs). The effects of flux contribution from an unseen
secondary were considered for the binary sample. We present the first
systematic study of the incidence of binarity for a sample of BSGs across the
theoretical terminal age main sequence (TAMS). To account for the distribution
of effective temperatures of the BSGs it may be necessary to extend the TAMS to
lower temperatures. This is consistent with the derived distribution of mass
discrepancies, projected rotational velocities (vsini) and N abundances,
provided that stars cooler than this temperature are post RSG objects. For the
BSGs in the Tarantula and previous FLAMES surveys, most have small vsini. About
10% have larger vsini (>100 km/s) but surprisingly these show little or no N
enhancement. All the cooler BSGs have low vsini of <70km/s and high N abundance
estimates, implying that either bi-stability braking or evolution on a blue
loop may be important. A lack of cool binaries, possibly reflects the small
sample size. Single star evolutionary models, which include rotation, can
account for the N enhancement in both the single and binary samples. The
detailed distribution of N abundances in the single and binary samples may be
different, possibly reflecting differences in their evolutionary history. The
first comparative study of single and binary BSGs has revealed that the main
sequence may be significantly wider than previously assumed, extending to
Teff=20000K. Some marginal differences in single and binary atmospheric
parameters and abundances have been identified, possibly implying non-standard
evolution for some of the sample. This sample as a whole has implications for
several aspects of our understanding of the evolution of BSGs. Full abstract in
paper | | Source: | arXiv, 1412.2705 | | Services: | Forum | Review | PDF | Favorites | |
|
|
No review found.
Did you like this article?
Note: answers to reviews or questions about the article must be posted in the forum section.
Authors are not allowed to review their own article. They can use the forum section.
browser claudebot
|
| |
|
|
|
|
News, job offers and information for researchers and scientists:
| |
REGISTER