Water line emission in low-mass protostars

Ceccarelli, C.; Loinard, L.; Caux, E.; Castets, A.; Tielens, A. G. G. M.; Molinari, S.; Liseau, R.; Smith, H. and White, G. (1999). Water line emission in low-mass protostars. In: The Physics and Chemistry of the Interstellar Medium, Proceedings of the 3rd Cologne-Zermatt Symposium, 22-25 Sep 1998, Zermatt, Switzerland.

URL: http://cdsads.u-strasbg.fr/abs/1999pcim.conf..283C


We present and analyse observations of several infrared lines of water obtained with the Long Wavelegth Spectrometer (LWS) on board the Infrared Space Observatory (ISO) towards three low luminosity protostars: IRAS16293-2422 in the σ-Ophiuchus complex, IRAS2 and IRAS4 in NGC1333. Those three sources have similar bolometric luminosities, excite powerful outflows, and have their strongest continuum emission at wavelengths larger than 100μm. They all belong to the youngest class of stellar objects known: the Class 0. In spite of their morphological and evolutionary similarity, our observations show large variations in their water line luminosities. The H2O lines provide insight into three key areas of low-mass protostar formation: the cloud chemistry and molecular/atomic abundances, cloud cooling mechanisms, and the shock environment. In this talk we will consider the two main mechanisms of water line emission in such young objects: emission from their surrounding envelopes and emission from the shocks created by their powerful outflows. Finally, we will speculate on the differences between the three sources.

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