Document Detail

Unexpectedly large mass loss during the thermal pulse cycle of the red giant star R Sculptoris.
MedLine Citation:
PMID:  23060194     Owner:  NLM     Status:  In-Process    
The asymptotic-giant-branch star R Sculptoris is surrounded by a detached shell of dust and gas. The shell originates from a thermal pulse during which the star underwent a brief period of increased mass loss. It has hitherto been impossible to constrain observationally the timescales and mass-loss properties during and after a thermal pulse--parameters that determine the lifetime of the asymptotic giant branch and the amount of elements returned by the star. Here we report observations of CO emission from the circumstellar envelope and shell around R Sculptoris with an angular resolution of 1.3″. What was previously thought to be only a thin, spherical shell with a clumpy structure is revealed to also contain a spiral structure. Spiral structures associated with circumstellar envelopes have been previously seen, leading to the conclusion that the systems must be binaries. Combining the observational data with hydrodynamic simulations, we conclude that R Sculptoris is a binary system that underwent a thermal pulse about 1,800 years ago, lasting approximately 200 years. About 3 × 10(-3) solar masses of material were ejected at a velocity of 14.3 km s(-1) and at a rate around 30 times higher than the pre-pulse mass-loss rate. This shows that about three times more mass was returned to the interstellar medium during and immediately after the pulse than previously thought.
M Maercker; S Mohamed; W H T Vlemmings; S Ramstedt; M A T Groenewegen; E Humphreys; F Kerschbaum; M Lindqvist; H Olofsson; C Paladini; M Wittkowski; I de Gregorio-Monsalvo; L-A Nyman
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Nature     Volume:  490     ISSN:  1476-4687     ISO Abbreviation:  Nature     Publication Date:  2012 Oct 
Date Detail:
Created Date:  2012-10-12     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  0410462     Medline TA:  Nature     Country:  England    
Other Details:
Languages:  eng     Pagination:  232-4     Citation Subset:  IM    
European Southern Observatory, Karl-Schwarzschild-Strasse 2, 85748 Garching, Germany.
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