Silicon in the dust formation zone of IRC+10216
2010 (English)In: Astronomy and Astrophysics, ISSN 0004-6361, E-ISSN 1432-0746, Vol. 518, L143- p.Article in journal (Refereed) Published
The interstellar medium is enriched primarily by matter ejected from evolved low and intermediate mass stars. The outflows from these stars create a circumstellar envelope in which a rich gas-phase and dust-nucleation chemistry takes place. We observed the nearest carbon-rich evolved star, IRC + 10216, using the PACS (55-210 mu m) and SPIRE (194-672 mu m) spectrometers on board Herschel. We find several tens of lines from SiS and SiO, including lines from the v = 1 vibrational level. For SiS these transitions range up to J = 124-123, corresponding to energies around 6700 K, while the highest detectable transition is J = 90-89 for SiO, which corresponds to an energy around 8400 K. Both species trace the dust formation zone of IRC + 10216, and the broad energy ranges involved in their detected transitions permit us to derive the physical properties of the gas and the particular zone in which each species has been formed. This allows us to check the accuracy of chemical thermodynamical equilibrium models and the suggested depletion of SiS and SiO due to accretion onto dust grains.
Place, publisher, year, edition, pages
2010. Vol. 518, L143- p.
techniques: spectroscopic, stars: AGB and post-AGB, stars: carbon, circumstellar matter, stars: mass-loss, stars: individual: IRC+10216
IdentifiersURN: urn:nbn:se:su:diva-51700DOI: 10.1051/0004-6361/201014562ISI: 000281527200144OAI: oai:DiVA.org:su-51700DiVA: diva2:385719
authorCount :392011-01-122011-01-122011-01-12Bibliographically approved