Crowther, P.A., Lennon, D.J., Walborn, N.R. et al. (1 more author) (2008) Properties of Galactic B supergiants. In: Mass Loss from Stars and the Evolution of Stellar Clusters. Astronomical Society of the Pacific Conference Series (388). Astronomical Society of the Pacific , p. 109. ISBN 978-1-58381-644-8
Abstract
Physical and wind properties of Galactic B supergiants are presented based upon non-LTE line blanketed model atmospheres, including Sher 25 toward the NGC 3603 cluster. We compare Halpha derived wind densities with recent results for SMC B supergiants and generally confirm theoretical expectations for stronger winds amongst Galactic supergiants. Mid B supergiant winds are substantially weaker than predictions from current radiatively driven wind theory, a problem which is exacerbated if winds are already clumped in the Halpha line forming region. We find that the so-called `bistability jump' at B1 (Teff ~ 21kK) from Lamers et al. is rather a more gradual downward trend. CNO elemental abundances, including Sher 25, reveal partially processed material at their surfaces. In general, these are in good agreement with evolutionary predictions for blue supergiants evolving redward accounting for rotational mixing. A few cases, including HD 152236 (zeta^1 Sco), exhibit strongly processed material which is more typical of Luminous Blue Variables. Our derived photospheric [N/O] ratio for Sher~25 agrees with that for its ejecta nebula, although a higher degree of CNO processing would be expected if the nebula originated during a red supergiant phase, as is suspected for the ring nebula ejected by the B supergiant progenitor of SN 1987A, Sk-69 202. Sher 25 has an inferred age of ~5Myr in contrast with ~2Myr for HD 97950, the ionizing cluster of NGC 3603. Sher 25 may be a foreground object or close binary evolution could be responsible for its unusual location in the H-R diagram.
Metadata
Item Type: | Book Section |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © 2008 Astronomical Society of the Pacific. This is an author produced version of a paper subsequently published in Astronomical Society of the Pacific Conference Series. Uploaded in accordance with the publisher's self-archiving policy. |
Keywords: | astro-ph; astro-ph |
Dates: |
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Institution: | The University of Sheffield |
Academic Units: | The University of Sheffield > Faculty of Science (Sheffield) > Department of Physics and Astronomy (Sheffield) |
Depositing User: | Symplectic Sheffield |
Date Deposited: | 25 Aug 2016 14:46 |
Last Modified: | 22 Mar 2018 06:40 |
Published Version: | http://www.aspbooks.org/a/volumes/article_details/... |
Status: | Published |
Publisher: | Astronomical Society of the Pacific |
Series Name: | Astronomical Society of the Pacific Conference Series |
Refereed: | Yes |
Related URLs: | |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:103979 |