Issue |
A&A
Volume 399, Number 2, February IV 2003
|
|
---|---|---|
Page(s) | 567 - 581 | |
Section | Interstellar and circumstellar matter | |
DOI | https://doi.org/10.1051/0004-6361:20021816 | |
Published online | 07 February 2003 |
Sulphur-bearing species as chemical clocks for low mass protostars?
1
Department of Physics, UMIST, PO Box 88, Manchester M60 1QD, UK
2
Joint Astronomy Centre, 660 North A'ohoku Place University Park Hilo, HI 96720, USA e-mail: G.Fuller@umist.ac.uk
Corresponding author: J. V. Buckle, j.buckle@jach.hawaii.edu
Received:
16
October
2001
Accepted:
5
December
2002
We present observations of , SO and towards a
sample of Class 0 and Class I sources. The abundances rule
out its formation in the gas phase and we assume that it is
released from grain mantles. Applying a model of the evolution of
the sulphur chemistry first used in the study of hot cores, we
show that this model can reproduce the results of our
observations even for the relatively low temperatures and
densities of these sources. We demonstrate that the chemical
evolution of sulphur bearing species is a potentially valuable
probe of chemical timescales in low mass star forming regions.
Overall, the model indicates that Class I sources are at a later
chemical evolutionary stage than their Class 0 counterparts, with
an average difference in chemical age of at least years and an upper limit on the age of the Class I sources of a few
times 105 years.
Key words: stars: formation / radio lines: ISM / ISM: abundances / astrochemistry
© ESO, 2003
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