TY - JOUR
T1 - A dynamical magnetosphere model for periodic Hα emission from the slowly rotating magnetic O star HD191612
AU - Sundqvist, Jon O.
AU - ud-Doula, Asif
AU - Owocki, Stanley P.
AU - Townsend, Richard H.D.
AU - Howarth, Ian D.
AU - Wade, Gregg A.
PY - 2012/6
Y1 - 2012/6
N2 - The magnetic O star HD191612 exhibits strongly variable, cyclic Balmer line emission on a 538-d period. We show here that its variable Hα emission can be well reproduced by the rotational phase variation of synthetic spectra computed directly from full radiation magnetohydrodynamical simulations of a magnetically confined wind. In slow rotators such as HD191612, wind material on closed magnetic field loops falls back to the star, but the transient suspension of material within the loops leads to a statistically overdense, low-velocity region around the magnetic equator, causing the spectral variations. We contrast such 'dynamical magnetospheres' (DMs) with the more steady-state 'centrifugal magnetospheres' of stars with rapid rotation, and discuss the prospects of using this DM paradigm to explain periodic line emission from also other non-rapidly rotating magnetic massive stars.
AB - The magnetic O star HD191612 exhibits strongly variable, cyclic Balmer line emission on a 538-d period. We show here that its variable Hα emission can be well reproduced by the rotational phase variation of synthetic spectra computed directly from full radiation magnetohydrodynamical simulations of a magnetically confined wind. In slow rotators such as HD191612, wind material on closed magnetic field loops falls back to the star, but the transient suspension of material within the loops leads to a statistically overdense, low-velocity region around the magnetic equator, causing the spectral variations. We contrast such 'dynamical magnetospheres' (DMs) with the more steady-state 'centrifugal magnetospheres' of stars with rapid rotation, and discuss the prospects of using this DM paradigm to explain periodic line emission from also other non-rapidly rotating magnetic massive stars.
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U2 - 10.1111/j.1745-3933.2012.01248.x
DO - 10.1111/j.1745-3933.2012.01248.x
M3 - Article
AN - SCOPUS:84868091741
SN - 1745-3933
VL - 423
SP - L21-L25
JO - Monthly Notices of the Royal Astronomical Society: Letters
JF - Monthly Notices of the Royal Astronomical Society: Letters
IS - 1
ER -