A dynamical magnetosphere model for periodic Hα emission from the slowly rotating magnetic O star HD191612

Jon O. Sundqvist, Asif ud-Doula, Stanley P. Owocki, Richard H.D. Townsend, Ian D. Howarth, Gregg A. Wade

Research output: Contribution to journalArticlepeer-review

47 Scopus citations

Abstract

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.

Original languageEnglish (US)
Pages (from-to)L21-L25
JournalMonthly Notices of the Royal Astronomical Society: Letters
Volume423
Issue number1
DOIs
StatePublished - Jun 2012

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science

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