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The Atmospheric Dynamics of alpha Tau (K5 III) - Clues to Understanding the Magnetic Dynamo in Late-Type Giant StarsUsing HST/GHRS, HST/STIS and FUSE archival data for alpha Tau and the CHIANTI spectroscopic code, we have derived line shifts, volumetric emission measures, and plasma density estimates, and calculated filling factors for a number of UV lines forming between 10,000 K and 300,000 K in the outer atmosphere of this red giant star. The data suggest the presence of low-temperature extended regions and high-temperature compact regions, associated with magnetically open and closed structures in the stellar atmosphere, respectively. The signatures of UV lines from alpha Tau can be consistently understood via a model of upward-traveling Alfven waves in a gravitationally stratified atmosphere. These waves cause non-thermal broadening in UV lines due to unresolved wave motions and downward plasma motions in compact magnetic loops heated by resonant Alfven wave heating.
Document ID
20080037989
Acquisition Source
Goddard Space Flight Center
Document Type
Conference Paper
Authors
Carpenter, Kenneth G. (NASA Goddard Space Flight Center Greenbelt, MD, United States)
Airapetian, Vladimir (Catholic Univ. of America Greenbelt, MD, United States)
Date Acquired
August 24, 2013
Publication Date
July 21, 2008
Subject Category
Astronomy
Meeting Information
Meeting: Cool Stars 15
Location: Saint Andrews, Scotland
Country: United Kingdom
Start Date: July 21, 2008
End Date: July 25, 2008
Sponsors: European Space Agency
Funding Number(s)
CONTRACT_GRANT: HST GO/AR 10956
CONTRACT_GRANT: HST GO/AR 9967
Distribution Limits
Public
Copyright
Public Use Permitted.

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