Near-Arcsecond Resolution Observations of the Hot Corino of the Solar-Type Protostar IRAS 16293–2422

Complex organic molecules have previously been discovered in solar-type protostars, raising the questions of where and how they form in the envelope. Possible formation mechanisms include grain mantle evaporation, the interaction of the outflow with its surroundings, and/or the impact of UV/X-rays inside the cavities. In this Letter we present the first interferometric observations of two complex molecules, CH3CN and HCOOCH3, toward the solar-type protostar IRAS 16293-2422. The images show that the emission originates from two compact regions centered on the two components of the binary system. We discuss how these results favor the grain mantle evaporation scenario, and we investigate the implications of these observations for the chemical composition and physical and dynamical state of the two components.

[1]  Physical-chemical modeling of the low-mass protostar IRAS 16293-2422 , 2004, astro-ph/0402610.

[2]  L. Mundy,et al.  The circumstellar structure of IRAS 16293-2422 - (C-18)O, NH3, and CO observations , 1990 .

[3]  Shudong Zhou.  Line Formation in Collapsing Cloud Cores with Rotation and Applications to B335 and IRAS 16293-2422 , 1995 .

[4]  A. Boss,et al.  Protostars and Planets VI , 2000 .

[5]  S. Cazaux,et al.  Complex Molecules in the Hot Core of the Low-Mass Protostar NGC 1333 IRAS 4A , 2004, astro-ph/0407154.

[6]  L. Mundy,et al.  IRAS 16293-2422: A Very Young Binary System , 1989 .

[7]  R. L. Brown,et al.  On the interpretation of carbon monoxide self-absorption profiles seen toward embedded stars in dense interstellar clouds. , 1977 .

[8]  E. F. Dishoeck,et al.  Does IRAS 16293–2422 have a hot core? Chemical inventory and abundance changes in its protostellar environment , 2002, astro-ph/0205457.

[9]  N. Evans,et al.  Modeling Line Profiles of Protostellar Collapse in B335 with the Monte Carlo Method , 1995 .

[10]  Lee G. Mundy,et al.  Unveiling the Circumstellar Envelope and Disk: A Subarcsecond Survey of Circumstellar Structures , 1999, astro-ph/9908301.

[11]  A. Sargent,et al.  Outflow-Infall Interactions in Early Star Formation and Their Impact on the Mass-assembling Process in L1228 , 2004 .

[12]  D. Teyssier,et al.  The Hot Core around the Low-Mass Protostar IRAS 16293–2422: Scoundrels Rule! , 2003 .

[13]  A. Tielens,et al.  Water emission in NGC 1333 IRAS 4 - The physical structure of the envelope , 2002, astro-ph/0209366.

[14]  Shudong Zhou.  In search of evidence for protostellar collapse - A systematic study of line formation in low-mass dense cores , 1992 .

[15]  A. Wootten.  The Duplicity of IRAS 16293-2422: A Protobinary Star? , 1989 .

[16]  E. F. Dishoeck,et al.  On the origin of H2CO abundance enhancements in low-mass protostars , 2004, astro-ph/0401635.

[17]  E. F. Dishoeck,et al.  Chemical evolution of star-forming regions. , 1998, Annual review of astronomy and astrophysics.

[18]  E. Young,et al.  Spectroscopic Evidence for Infall around an Extraordinary IRAS Source in Ophiuchus , 1986 .

[19]  A. Tielens,et al.  The H2CO abundance in the inner warm regions of low mass protostellar envelopes , 2003, astro-ph/0310536.