Open AccessSlingshot prominences above stellar X‐ray coronae
Author(s) -
Jardine M.,
Van Ballegooijen A. A.
Publication year - 2005
Publication title -
monthly notices of the royal astronomical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.058
H-Index - 383
eISSN - 1365-2966
pISSN - 0035-8711
DOI - 10.1111/j.1365-2966.2005.09256.x
Subject(s) - physics , solar prominence , astrophysics , corona (planetary geology) , radius , coronal loop , stars , stellar rotation , rotation (mathematics) , astronomy , starspot , solar radius , rotation period , magnetic field , solar wind , coronal mass ejection , geometry , quantum mechanics , computer security , mathematics , astrobiology , venus , computer science
We present a new model for the coronal structure of rapidly rotating solar‐type stars. The presence of prominences trapped in co‐rotation 2–5 stellar radii above the stellar surface has been taken as evidence that the coronae of these stars must be very extended. The observed surface magnetic fields, however, cannot contain X‐ray emitting gas out to these distances. We present an alternative model: that these prominences are trapped in long thin loops embedded not in the X‐ray corona, but in the wind. Above coronal helmet streamers, oppositely directed wind‐bearing field lines reconnect to form closed loops, which then fill up with gas that was originally part of the wind. We demonstrate that static equilibria exist for these loops at a range of pressures and temperatures. The maximum loop height falls as the rotation rate increases, but rises as the loop temperature decreases. For a solar mass star with a rotation period of 0.5 d, whose X‐ray corona extends 1 R ★ above the surface, loops at temperatures of 10 4 K can extend out to 5 R ★ .