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Astron. Astrophys. 333, L83-L86 (1998)

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Letter to the Editor

On the spin-down of Be stars

John M. Porter

Astrophysics Research Institute, School of Engineering, Liverpool John Moores University, Byrom Street, Liverpool L3 3AF, UK

Received 6 March 1998 / Accepted 31 March 1998


The spin-down of Be stars due to angular momentum transport from star to disc has been considered. This has been prompted by empirical studies of observed optical and IR line profile studies indicating that the disc is rotating in a Keplerian fashion. It is found that substantial spin-down may occur, especially for late B stars throughout their main-sequence lives for the "strongest" discs (most dense [FORMULA] g cm-3 with high radial velocity [FORMULA] at their inner edge and with large opening angle [FORMULA]). This is in conflict with studies of rotational velocity distributions for different luminosity classes, which show no significant evolution. The implications of this for Be star discs are considered.

Key words: stars: emission-line, Be – stars: rotation – stars: evolution – circumstellar matter


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© European Southern Observatory (ESO) 1998

Online publication: April 28, 1998