000002202 001__ 2202
000002202 005__ 20160701171701.0
000002202 0247_ $$2DOI$$a10.1038/nature11511
000002202 037__ $$aASTROimport-359
000002202 100__ $$aMaercker, M.
000002202 245__ $$aUnexpectedly large mass loss during the thermal pulse cycle of the red giant star R Sculptoris
000002202 260__ $$c2012
000002202 520__ $$aThe asymptotic-giant-branch star R Sculptoris is surrounded by a detached shell of dust and gas. The shell originates from a thermal pulse during which the star underwent a brief period of increased mass loss. It has hitherto been impossible to constrain observationally the timescales and mass-loss properties during and after a thermal pulse--parameters that determine the lifetime of the asymptotic giant branch and the amount of elements returned by the star. Here we report observations of CO emission from the circumstellar envelope and shell around R Sculptoris with an angular resolution of 1.3''. What was previously thought to be only a thin, spherical shell with a clumpy structure is revealed to also contain a spiral structure. Spiral structures associated with circumstellar envelopes have been previously seen, leading to the conclusion that the systems must be binaries. Combining the observational data with hydrodynamic simulations, we conclude that R Sculptoris is a binary system that underwent a thermal pulse about 1,800 years ago, lasting approximately 200 years. About 3 × 10-3 solar masses of material were ejected at a velocity of 14.3 km s-1 and at a rate around 30 times higher than the pre-pulse mass-loss rate. This shows that about three times more mass was returned to the interstellar medium during and immediately after the pulse than previously thought. 
000002202 700__ $$a Mohamed, S.
000002202 700__ $$a Vlemmings, W. H. T.
000002202 700__ $$a Ramstedt, S.
000002202 700__ $$a Groenewegen, M. A. T.
000002202 700__ $$a Humphreys, E.
000002202 700__ $$a Kerschbaum, F.
000002202 700__ $$a Lindqvist, M.
000002202 700__ $$a Olofsson, H.
000002202 700__ $$a Paladini, C.
000002202 700__ $$a Wittkowski, M.
000002202 700__ $$a de Gregorio-Monsalvo, I.
000002202 700__ $$a Nyman, L.-A.
000002202 773__ $$c232-234$$i7419$$pNature$$v490$$y2012
000002202 85642 $$ahttp://esoads.eso.org/abs/2012Natur.490..232M
000002202 905__ $$apublished in
000002202 980__ $$aREFERD