Low-mass star formation in R Coronae Australis: observations of organic molecules with the APEX telescope

Free access article

Issue		A&A Volume 454, Number 2, August I 2006 APEX Special Booklet


Page(s)		L67 - L70
Section		Letters
DOI		http://dx.doi.org/10.1051/0004-6361:20065334

A&A 454, L67-L70 (2006)
DOI: 10.1051/0004-6361:20065334

Letter

Low-mass star formation in R Coronae Australis: observations of organic molecules with the APEX telescope

F. L. Schöier¹, J. K. Jørgensen², K. M. Pontoppidan³ and A. A. Lundgren⁴

¹ Stockholm Observatory, AlbaNova University Center, 106 91 Stockholm, Sweden
e-mail: fredrik@astro.su.se
² Harvard-Smithsonian Center for Astrophysics, 60 Garden Street MS42, Cambridge, MA 02138, USA
³ Division of Geological and Planetary Sciences, California Institute of Technology, MS 150-21, Pasadena, CA 91125, USA
⁴ European Southern Observatory, Casilla 19001, Santiago 19, Chile

(Received 31 March 2006 / Accepted 15 May 2006)

Abstract
This paper presents new APEX submillimetre molecular line observations of three low-mass protostars, IRS7A, IRS7B, and IRAS32, in the R Coronae Australis molecular cloud complex. The molecular excitation analysis is performed using a statistical equilibrium radiative transfer code. The derived beam averaged fractional abundances vary by less than a factor of two among the three sources, except those of H₂CO and CH₃OH, which show differences of about an order of magnitude. The molecular abundances are similar to those typically found in other star-forming regions in the Galaxy, such as the $\rho$ Oph and Perseus molecular clouds. There is a marked difference in the kinetic temperatures derived for the protobinary source IRS7 from H₂CO ( $\approx$ 40-60 K) and CH₃OH ( $\approx$ 20 K), possibly indicating a difference in origin of the emission from these two molecules.

Key words: stars: formation -- ISM: molecules -- ISM: abundances -- astrochemistry

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