The solar type protostar IRAS16293-2422: new constraints on the physical structure

¹ Laboratoire d'Astrophysique, Observatoire de Grenoble, 38041 Grenoble, France e-mail: [Nicolas.Crimier;Cecilia.Ceccarelli;Sebastien.Maret;Claudine.Kahane]@obs.ujf-grenoble.fr
² CESR-UPS, Centre National de la Recherche Scientifique, Toulouse, France e-mail: Sandrine.Bottinelli@cesr.fr
³ California Institute of Technology, MC 301-17, Pasadena, CA 91125, USA e-mail: dcl@caltech.edu

Received: 12 August 2009
Accepted: 23 March 2010

Abstract

Context. The low mass protostar IRAS16293-2422 is a prototype Class 0 source in studies of the chemical structure during the initial phases of life of solar type stars.

Aims. To derive the chemical structure accurately, a precise determination of the source physical structure is required. The goal of this study is to derive the structure of IRAS16293-2422.

Methods. We reanalyzed all available continuum data (single dish and interferometric, from millimeter to MIR) to derive accurate density and dust temperature profiles. Using ISO observations of water, we also reconstructed the gas temperature profile.

Results. Our analysis shows that the envelope surrounding IRAS16293-2422 is described well by the Shu “inside-out” collapsing envelope model or a single power-law density profile with index equal to 1.8. In contrast to some previous studies, our analysis does not show evidence of a large (≥800 AU in diameter) cavity.

Conclusions. Although IRAS16293-2422 is a multiple system composed of two or three objects, our reconstruction will be useful in deriving the chemical structure of the large cold envelope surrounding these objects and the warm component, treated here as a single source, from single-dish observations of molecular emission.