WISHes coming true: water in low-mass star-forming regions with Herschel

¹ Leiden Observatory, Leiden University, PO Box 9513, 2300RA Leiden, The Netherlands
² MPE, Giesenbachstrasse 1, 85748 Garching, Germany
³ Department of Physics and Astronomy, Denison University, Granville, OH 43023, USA
⁴ Centre for Star and Planet Formation, Natural History Museum of Denmark, University of Copenhagen, Øster Voldgade 5-7, 1350 Copenhagen K., Denmark
⁵ Institute of Astronomy, ETH Zurich, 8093 Zurich, Switzerland

Abstract

Water is a key molecule for tracing physical and chemical processes in star-forming regions. The key program “Water in star-forming regions with Herschel” is observing several water transitions towards low-mass protostars with HIFI. Results regarding the 557 GHz transition of water are reported here showing that the line is surprisingly broad, and consists of several different velocity components. The bulk of the emission comes from shocks, where the abundance is increased by several orders of magnitude to  ~10^-4. The abundance of water in the outer envelope is determined to  ~10^-8, whereas only an upper limit of 10^-5 is derived for the inner, warm envelope.