A high-resolution spectropolarimetric survey of herbig Ae/Be stars - II. rotation

Alecian, E. and Wade, G. A. and Catala, C. and Grunhut, J. H. and Landstreet, J. D. and Bohm, T. and Folsom, C. P. and Marsden, S. (2013) A high-resolution spectropolarimetric survey of herbig Ae/Be stars - II. rotation. Monthly Notices of the Royal Astronomical Society , 429 (2). pp. 1027-1038. ISSN 0035-8711

Abstract

We report the analysis of the rotational properties of our sample of Herbig Ae/Be (HAeBe) and related stars for which we have obtained high-resolution spectropolarimetric observations. Using the projected rotational velocities measured at the surface of the stars, we have calculated the angular momentum of the sample and plotted it as a function of age. We have then compared the angular momentum and the v sin i distributions of themagnetic to the non-magnetic HAeBe stars. Finally, we have predicted v sin i of the non-magnetic, non-binary ('normal') stars in our sample when they reach the zero-age main sequence (ZAMS), and compared them to various catalogues of v sin i of main-sequence stars. First, we observe that magnetic HAeBe stars are much slower rotators than normal stars, indicating that they have been more efficiently braked than the normal stars. In fact, the magnetic stars have already lost most of their angular momentum, despite their young ages (lower than 1 Myr for some of them). Secondly, our analysis suggests that the low-mass (1.5 < M < 5M·) normal HAeBe stars evolve with constant angular momentum towards the ZAMS, while the high-mass normal HAeBe stars (M > 5M·) are losing angular momentum. We propose that winds, which are expected to be stronger in massive stars, are at the origin of this phenomenon.


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Item Type: Article (Commonwealth Reporting Category C)
Refereed: Yes
Item Status: Live Archive
Additional Information: © 2012 The Authors. All rights are reserved and no materials may be copied, modified, published, broadcast or otherwise distributed without the prior written permission of the publisher.
Faculty / Department / School: Historic - Faculty of Sciences - No Department
Date Deposited: 19 Sep 2013 00:01
Last Modified: 14 Jul 2014 06:39
Uncontrolled Keywords: early-type stars; magnetic field; pre-main-sequence; rotation
Fields of Research : 02 Physical Sciences > 0201 Astronomical and Space Sciences > 020110 Stellar Astronomy and Planetary Systems
02 Physical Sciences > 0201 Astronomical and Space Sciences > 020102 Astronomical and Space Instrumentation
02 Physical Sciences > 0205 Optical Physics > 020503 Nonlinear Optics and Spectroscopy
Socio-Economic Objective: E Expanding Knowledge > 97 Expanding Knowledge > 970102 Expanding Knowledge in the Physical Sciences
Identification Number or DOI: 10.1093/mnras/sts384
URI: http://eprints.usq.edu.au/id/eprint/23794

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