Methanol emission from low mass protostars
CASTETS, Alain
Laboratoire d'astrodynamique, d'astrophysique et d'aéronomie de bordeaux [L3AB]
Laboratoire d'Astrophysique de Bordeaux [Pessac] [LAB]
Observatoire aquitain des sciences de l'univers [OASU]
< Reduce
Laboratoire d'astrodynamique, d'astrophysique et d'aéronomie de bordeaux [L3AB]
Laboratoire d'Astrophysique de Bordeaux [Pessac] [LAB]
Observatoire aquitain des sciences de l'univers [OASU]
Language
en
Article de revue
This item was published in
Astronomy and Astrophysics - A&A. 2005, vol. 442, n° 2, p. 527-538
EDP Sciences
English Abstract
We present observations of methanol lines in a sample of Class 0 low mass protostars. Using a 1-D radiative transfer model, we derive the abundances in the envelopes. In two sources of the sample, the observations can only ...Read more >
We present observations of methanol lines in a sample of Class 0 low mass protostars. Using a 1-D radiative transfer model, we derive the abundances in the envelopes. In two sources of the sample, the observations can only be reproduced by the model if the methanol abundance is enhanced by about two order of magnitude in the inner hot region of the envelope. Two other sources show similar jumps, although at a lower confidence level. The observations for the other three sources are well reproduced with a constant abundance, but the presence of a jump cannot be ruled out. The observed methanol abundances in the warm gas around low mass protostars are orders of magnitude higher than gas phase chemistry models predict. Hence, in agreement with other evidences, this suggest that the high methanol abundance reflects recent evaporation of ices due to the heating by the newly formed star. The observed abundance ratios of CH3 OH, H2 CO, and CO are in good agreement with grain surface chemistry models. However, the absolute abundances are more difficult to reproduce and may point towards the presence of multiple ice components in these regions.Read less <
English Keywords
ISM: abundances
ISM: molecules
stars: formation
Origin
Hal imported