1. Department of Physics and Astronomy, University of Rochester, Rochester, New York 14627-0171, USA
2. Department of Astronomy, University of Virginia, Charlottesville, Virginia 22904, USA
3. NASA Astrobiology Institute, and,
4. Department of Physics and Astronomy, UCLA, Los Angeles, California 90095, USA
5. NOAO, Tucson, Arizona 85719, USA
6. Department of Astronomy, University of Michigan, Ann Arbor, Michigan 48109, USA
7. Centro de Radioastronomía y Astrofísica, UNAM, 58089 Morelia, Michoacán, Mexico
8. Center for Radiophysics and Space Research, Cornell University, Ithaca, New York 14853, USA

Correspondence to: Dan M. Watson¹ Correspondence and requests for materials should be addressed to D.M.W. (Email: dmw@pas.rochester.edu).

Class 0 protostars, the youngest type of young stellar objects, show many signs of rapid development from their initial, spheroidal configurations, and therefore are studied intensively for details of the formation of protoplanetary disks within protostellar envelopes. At millimetre wavelengths, kinematic signatures of collapse have been observed in several such protostars, through observations of molecular lines that probe their outer envelopes. It has been suggested that one or more components of the proto-multiple system NGC 1333–IRAS 4 (refs 1, 2) may display signs of an embedded region that is warmer and denser than the bulk of the envelope^{3, 4}. Here we report observations that reveal details of the core on Solar System dimensions. We detect in NGC 1333–IRAS 4B a rich emission spectrum of H₂O, at wavelengths 20–37 m, which indicates an origin in extremely dense, warm gas. We can model the emission as infall from a protostellar envelope onto the surface of a deeply embedded, dense disk, and therefore see the development of a protoplanetary disk. This is the only example of mid-infrared water emission from a sample of 30 class 0 objects, perhaps arising from a favourable orientation; alternatively, this may be an early and short-lived stage in the evolution of a protoplanetary disk.

MORE ARTICLES LIKE THIS

These links to content published by NPG are automatically generated.