A Rigidly rotating magnetosphere model for circumstellar emission from magnetic OB stars
Aug, 2004
15 pages
Published in:
- Mon.Not.Roy.Astron.Soc. 357 (2005) 251-264
e-Print:
- astro-ph/0408565 [astro-ph]
View in:
Citations per year
Abstract: (arXiv)
We present a semi-analytical approach for modeling circumstellar emission from rotating hot stars with a strong dipole magnetic field tilted at an arbitrary angle to the rotation axis. By assuming the rigid-field limit in which material driven (e.g., in a wind outflow) from the star is forced to remain in strict rigid-body co-rotation, we are able to solve for the effective centrifugal-plus-gravitational potential along each field line, and thereby identify the location of potential minima where material is prone to accumulate. Applying basic scalings for the surface mass flux of a radiatively driven stellar wind, we calculate the circumstellar density distribution that obtains once ejected plasma settles into hydrostatic stratification along field lines. The resulting accumulation surface resembles a rigidly rotating, warped disk, tilted such that its average surface normal lies between the rotation and magnetic axes. Using a simple model of the plasma emissivity, we calculate time-resolved synthetic line spectra for the disk. Initial comparisons show an encouraging level of correspondence with the observed rotational phase variations of Balmer-line emission profiles from magnetic Bp stars like sigma Ori E.Note:
- 15 pages, 4 figures, submitted to MNRAS, revised version based on referee's remarks
References(32)
Figures(0)