Astronomy and Astrophysics – Astrophysics
Scientific paper
2006-03-24
Astron.Astrophys.454:609-615,2006
Astronomy and Astrophysics
Astrophysics
LaTeX v5.2, 9 pages, 10 Postscript figures, to be published in Astronomy & Astrophysics
Scientific paper
10.1051/0004-6361:20054792
In this study we test the possibility that the asymmetry in the profiles of the H-alpha and Ca II K lines in red giant stars is due to the presence of an active chromosphere rather than to mass loss. To this end, we compare line profiles computed using relevant model chromospheres to profiles of the H-alpha and Ca II K lines observed in five red giant stars of the globular cluster NGC 2808. The spectra were taken with FLAMES during Science Verification, using the UVES mode at high resolution (R=43,000) for the H-alpha line, and GIRAFFE in MEDUSA mode (R=20,000) for the Ca II K line. We find that the observed profiles are better described if a negative (outward) velocity field is included in the model chromospheres. This leads to mass loss rates of a few 10**(-9) solar masses per year, very close to the requirements of the stellar evolution theory.
Cacciari Carla
Mauas Pablo J. D.
Pasquini Luca
No associations
LandOfFree
Modelling Chromospheric Line Profiles in NGC2808: Evidence of Mass Loss from RGB Stars does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Modelling Chromospheric Line Profiles in NGC2808: Evidence of Mass Loss from RGB Stars, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Modelling Chromospheric Line Profiles in NGC2808: Evidence of Mass Loss from RGB Stars will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-90420