Sign on

SAO/NASA ADS Astronomy Abstract Service

· Find Similar Abstracts (with default settings below)
· Electronic Refereed Journal Article (HTML)
· Full Refereed Journal Article (PDF/Postscript)
· arXiv e-print (arXiv:0902.1751)
· References in the article
· Citations to the Article (16) (Citation History)
· Refereed Citations to the Article
· SIMBAD Objects (21)
· Also-Read Articles (Reads History)
·
· Translate This Page
Title:
Rotational mixing in massive binaries. Detached short-period systems
Authors:
de Mink, S. E.; Cantiello, M.; Langer, N.; Pols, O. R.; Brott, I.; Yoon, S.-Ch.
Affiliation:
AA(Astronomical Institute, Utrecht University, PO Box 80000, 3508 TA Utrecht, The Netherlands ), AB(Astronomical Institute, Utrecht University, PO Box 80000, 3508 TA Utrecht, The Netherlands ), AC(Astronomical Institute, Utrecht University, PO Box 80000, 3508 TA Utrecht, The Netherlands ; Argelander-Institut für Astronomie der Universität Bonn, Auf dem Hügel 71, 53121 Bonn, Germany), AD(Astronomical Institute, Utrecht University, PO Box 80000, 3508 TA Utrecht, The Netherlands ), AE(Astronomical Institute, Utrecht University, PO Box 80000, 3508 TA Utrecht, The Netherlands ), AF(Dep. of Astronomy & Astrophysics, Univ. of California, Santa Cruz, CA95064, USA )
Publication:
Astronomy and Astrophysics, Volume 497, Issue 1, 2009, pp.243-253 (A&A Homepage)
Publication Date:
04/2009
Origin:
EDP Sciences
Keywords:
binaries: close, stars: rotation, stars: abundances, Magellanic Clouds, stars: Wolf-Rayet, X-rays: binaries
DOI:
10.1051/0004-6361/200811439
Bibliographic Code:
2009A&A...497..243D

Abstract

Models of rotating single stars can successfully account for a wide variety of observed stellar phenomena, such as the surface enhancements of N and He observed in massive main-sequence stars. However, recent observations have questioned the idea that rotational mixing is the main process responsible for the surface enhancements, emphasizing the need for a strong and conclusive test for rotational mixing. We investigate the consequences of rotational mixing for massive main-sequence stars in short-period binaries. In these systems the tides are thought to spin up the stars to rapid rotation, synchronous with their orbital revolution. We use a state-of-the-art stellar evolution code including the effect of rotational mixing, tides, and magnetic fields. We adopt a rotational mixing efficiency that has been calibrated against observations of rotating stars under the assumption that rotational mixing is the main process responsible for the observed surface abundances. We find that the primaries of massive close binaries (M1 ≈ 20 {M}ȯ, P_orb ≲ 3 days) are expected to show significant enhancements in nitrogen (up to 0.6 dex in the Small Magellanic Cloud) for a significant fraction of their core hydrogen-burning lifetime. We propose using such systems to test the concept of rotational mixing. As these short-period binaries often show eclipses, their parameters can be determined with high accuracy. For the primary stars of more massive and very close systems (M1 ≈ 50 {M}ȯ, P_orb≲ 2 days) we find that centrally produced helium is efficiently mixed throughout the envelope. The star remains blue and compact during the main sequence evolution and stays within its Roche lobe. It is the less massive star, in which the effects of rotational mixing are less pronounced, which fills its Roche lobe first, contrary to what standard binary evolution theory predicts. The primaries will appear as “Wolf-Rayet stars in disguise”: core hydrogen-burning stars with strongly enhanced He and N at the surface. We propose that this evolution path provides an alternative channel for the formation of tight Wolf-Rayet binaries with a main-sequence companion and might explain massive black hole binaries such as the intriguing system M33 X-7.
Bibtex entry for this abstract   Preferred format for this abstract (see Preferences)
   

Find Similar Abstracts:

Use: Authors
Title
Keywords (in text query field)
Abstract Text
Return: Query Results Return    items starting with number
Query Form
Database: Astronomy
Physics
arXiv e-prints