Probing the mass-loss history of the unusual Mira variable R Hydrae through its infrared CO wind
Abstract
Context: The unusual Mira variable
Aims: The goal of this study is to probe the circumstellar envelope (CSE) around R Hya and to check for a correlation between the derived density structure and the declining period.
Methods: We investigate the CSE around
Results: The combined analysis bear evidence of a change in mass-loss rate some 220 yr ago (at 150 Rstar or 1.9 arcsec from the star). While the mass-loss rate before ad 1770 is estimated to be 2 × 10-7 M⊙/yr, the present day mass-loss rate is a factor of 20 lower. The derived mass-loss history nicely agrees with the mass-loss rate estimates by Zijlstra et al. (2002) on the basis of the period decline. Moreover, the recent detection of an AGB-ISM bow shock around
Conclusions: Our results give empirical evidence to the thermal-pulse model, which is capable of explaining both the period evolution and the mass-loss history of
- Publication:
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Astronomy and Astrophysics
- Pub Date:
- June 2008
- DOI:
- 10.1051/0004-6361:20079312
- Bibcode:
- 2008A&A...484..401D
- Keywords:
-
- line: profiles;
- radiative transfer;
- stars: AGB and post-AGB;
- stars: circumstellar matter;
- stars: mass-loss;
- stars: individual: <ASTROBJ>R Hya</ASTROBJ>