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Astron. Astrophys. 317, L5-L8 (1997)

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1. Introduction

Bok & Reilly (1947) and Bok (1948) were the first to suggest that the small, isolated dark clouds called Bok globules are the birthplaces of low mass stars. Infrared observations made by the IRAS have revealed embedded sources, probably young stellar objects (YSOs), inside these clouds (Yun & Clemens 1990; Clemens et al. 1991). Some of these sources drive a molecular outflow (Yun & Clemens 1992), confirming star-forming activity in globules.

In order to identify a true protostar located in a cloud core, it is necessary to have kinematic evidence of mass infall. This is best accomplished through high spatial and spectral resolution molecular line observations. One of the best candidates for a collapsing protostar is located in the globule B335 (Frerking et al. 1987; Zhou et al. 1990; Zhou et al. 1993; Choi et al. 1995; Zhou 1995).

By comparing the properties of globules with and without star formation one can study the processes that lead to star formation in molecular clouds. Lehtinen et al. (1995) have studied a globule without any signs of star formation, the Thumbprint Nebula (TPN) in the Chamaeleon III region. In order to study the properties of molecular gas in a star forming globule, we observed the globule DC 303.8-14.2 (Hartley et al. 1986), located in the eastern part of the Chamaeleon II dark cloud complex, which is at a distance of 200 pc (Whittet et al. 1991; Hughes & Hartigan 1992). It is of a similar size and appearance as the TPN but it harbours an IRAS point source (IRAS 13036-7644, [FORMULA], [FORMULA] ) with a spectral energy distribution typical for a young stellar object.

In this Letter we present the first results of our extensive molecular line study of DC 303.8-14.2. We discuss the observed line profiles which display the signature of mass infall towards the IRAS source.

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© European Southern Observatory (ESO) 1997