Unexpectedly large mass loss during the thermal pulse cycle of the red giant star R Sculptoris
Artikel i vetenskaplig tidskrift, 2012

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 undergoes 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 on 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 arcsec. What was hitherto thought to be only a thin, spherical shell with a clumpy structure, is revealed to contain a spiral structure. Spiral structures associated with circumstellar envelopes have been seen previously, from which it was concluded that the systems must be binaries. Using the data, combined with hydrodynamic simulations, we conclude that R Sculptoris is a binary system that underwent a thermal pulse approximately 1800 years ago, lasting approximately 200 years. About 0.003 Msun of mass was ejected at a velocity of 14.3 km s-1 and at a rate approximately 30 times higher than the prepulse mass-loss rate. This shows that approximately 3 times more mass is returned to the interstellar medium during and immediately after a pulse than previously thought.

Författare

Matthias Maercker

European Southern Observatory (ESO)

Universität Bonn

S. Mohamed

South African Astronomical Observatory

Wouter Vlemmings

Chalmers, Rymd- och geovetenskap, Radioastronomi och astrofysik

S. Ramstedt

Universität Bonn

M. A. T. Groenewegen

Royal Observatory of Belgium

E. M. Humphreys

European Southern Observatory (ESO)

F. Kerschbaum

Universität Wien

Michael Lindqvist

Chalmers, Rymd- och geovetenskap, Onsala rymdobservatorium

Hans Olofsson

Chalmers, Rymd- och geovetenskap, Onsala rymdobservatorium

C. Paladini

Universität Wien

M. Wittkowski

European Southern Observatory (ESO)

I. de Gregorio-Monsalvo

Atacama Large Millimeter-submillimeter Array

Lars-Åke Nyman

Atacama Large Millimeter-submillimeter Array

Nature

0028-0836 (ISSN) 1476-4687 (eISSN)

Vol. 490 232-234

Ämneskategorier

Astronomi, astrofysik och kosmologi

Fundament

Grundläggande vetenskaper

Infrastruktur

Onsala rymdobservatorium

DOI

10.1038/nature11511