Magellanic Cloud WC/WO Wolf-Rayet stars : I. Binary frequency and Roche lobe overflow formation

A nearly complete sample of 24 Magellanic Cloud WC/WO subclass Wolf–Rayet stars is studied spectroscopically and photometrically to determine its binary frequency. Theory predicts the Roche lobe overflow produced Wolf–Rayet binary frequency to be 52±14 per cent in the Large Magellanic Cloud and 100...

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Detalles Bibliográficos
Autores principales: Bartzakos, P., Moffat, Anthony, Niemelä, Virpi Sinikka
Formato: Articulo
Lenguaje:Inglés
Publicado: 2001
Materias:
Ciencias Astronómicas
astrofísica
atlases; binaries: spectroscopic; stars: Wolf-Rayet; Magellanic Clouds
Acceso en línea:http://sedici.unlp.edu.ar/handle/10915/2075
http://onlinelibrary.wiley.com/doi/10.1046/j.1365-8711.2001.04126.x/full
Aporte de:
SEDICI (UNLP) de Universidad Nacional de La Plata
id I19-R120-10915-2075
record_format dspace
institution Universidad Nacional de La Plata
institution_str I-19
repository_str R-120
collection SEDICI (UNLP)
language Inglés
topic Ciencias Astronómicas
astrofísica
atlases; binaries: spectroscopic; stars: Wolf-Rayet; Magellanic Clouds
spellingShingle Ciencias Astronómicas
astrofísica
atlases; binaries: spectroscopic; stars: Wolf-Rayet; Magellanic Clouds
Bartzakos, P.
Moffat, Anthony
Niemelä, Virpi Sinikka
Magellanic Cloud WC/WO Wolf-Rayet stars : I. Binary frequency and Roche lobe overflow formation
topic_facet Ciencias Astronómicas
astrofísica
atlases; binaries: spectroscopic; stars: Wolf-Rayet; Magellanic Clouds
description A nearly complete sample of 24 Magellanic Cloud WC/WO subclass Wolf–Rayet stars is studied spectroscopically and photometrically to determine its binary frequency. Theory predicts the Roche lobe overflow produced Wolf–Rayet binary frequency to be 52±14 per cent in the Large Magellanic Cloud and 100 per cent in the Small Magellanic Cloud, not counting non-Roche lobe overflow Wolf–Rayet binaries. Lower ambient metallicity (Z) leads to lower opacity, preventing all but the most massive (hence luminous) single stars from reaching the Wolf–Rayet stage. However, theory predicts that Roche lobe overflow even in binaries of modest mass will lead to Wolf–Rayet stars in binaries with periods below approximately 200 d, for initial periods below approximately 1000 d, independent of Z. By examining their absolute continuum magnitudes, radial velocity variations, emission-line equivalent widths and full widths at half-maximum, a WC/WO binary frequency of only 13 per cent, significantly lower than the prediction, is found in the Large Magellanic Cloud. In the unlikely event that all of the cases with a less certain binary status actually turn out to be binary, current theory and observation would agree. (The Small Magellanic Cloud contains only one WC/WO star, which happens to be a binary.) The three WC+O binaries in the Large Magellanic Cloud all have periods well below 1000 d. The large majority of WC/WO stars in such environments apparently can form without the aid of a binary companion. Current evolutionary scenarios appear to have difficulty explaining either the relatively large number of Wolf–Rayet stars in the Magellanic Clouds, or the formation of Wolf–Rayet stars in general.
format Articulo
Articulo
author Bartzakos, P.
Moffat, Anthony
Niemelä, Virpi Sinikka
author_facet Bartzakos, P.
Moffat, Anthony
Niemelä, Virpi Sinikka
author_sort Bartzakos, P.
title Magellanic Cloud WC/WO Wolf-Rayet stars : I. Binary frequency and Roche lobe overflow formation
title_short Magellanic Cloud WC/WO Wolf-Rayet stars : I. Binary frequency and Roche lobe overflow formation
title_full Magellanic Cloud WC/WO Wolf-Rayet stars : I. Binary frequency and Roche lobe overflow formation
title_fullStr Magellanic Cloud WC/WO Wolf-Rayet stars : I. Binary frequency and Roche lobe overflow formation
title_full_unstemmed Magellanic Cloud WC/WO Wolf-Rayet stars : I. Binary frequency and Roche lobe overflow formation
title_sort magellanic cloud wc/wo wolf-rayet stars : i. binary frequency and roche lobe overflow formation
publishDate 2001
url http://sedici.unlp.edu.ar/handle/10915/2075
http://onlinelibrary.wiley.com/doi/10.1046/j.1365-8711.2001.04126.x/full
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AT niemelavirpisinikka magellaniccloudwcwowolfrayetstarsibinaryfrequencyandrochelobeoverflowformation
bdutipo_str Repositorios
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