EDP Sciences
Free access
Volume 416, Number 2, March III 2004
Page(s) 631 - 640
Section Interstellar and circumstellar matter
DOI http://dx.doi.org/10.1051/0004-6361:20034123

A&A 416, 631-640 (2004)
DOI: 10.1051/0004-6361:20034123

L1157: Interaction of the molecular outflow with the Class 0 environment

M. T. Beltrán1, 2, F. Gueth3, S. Guilloteau3 and A. Dutrey4

1  Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138, USA
2  Osservatorio Astrofisico di Arcetri, Largo E. Fermi 5, 50125 Firenze, Italy
3  Institut de Radio Astronomie Millimétrique, 300 rue de la Piscine, 38406 Saint Martin d'Hères, France
4  Laboratoire d'Astrophysique de l'Observatoire de Grenoble, BP 53, 38041 Grenoble, France

(Received 28 July 2003 / Accepted 3 December 2003 )

We present high angular resolution interferometric observations of the dust continuum at 2.7 and 1.3 mm, and of the HC 3N ( $J=12\to11$) and C 18O ( $J=2\to1$) emission around L1157-mm, a Class 0 object that drives a spectacular molecular outflow. The millimeter dust emission is clearly resolved into two components, a flattened compact source of ~ $450\times250$ AU at 1.3 mm, and mass ~0.1  $M_\odot$, plus an extended envelope of ~3000 AU at 1.3 mm, and mass ~1.1  $M_\odot$. The millimeter spectral index varies throughout the region, with the lower value found toward the compact protostar, possibly indicating grain growth in the denser regions. A strong interaction between the molecular outflow and the close protostellar environment is taking place and affects the structure of the innermost parts of the envelope. This is shown by the spatial coincidence between the molecular outflow and the dust (1.3 mm continuum) and HC 3N emission: both tracers show structures associated to the edges of the outflow lobes. Basically, the global picture sketched for the Class 0 object L1157-mm by Gueth et al. (1997) is supported. We find possible evidence of infall, but we do not detect any velocity gradient indicative of a rotating circumstellar disk.

Key words: stars: individual: L1157 -- stars: formation -- stars: circumstellar matter -- ISM: dust, extinction -- ISM: molecules

Offprint request: F. Gueth, gueth@iram.fr

SIMBAD Objects

© ESO 2004