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Chemistry of Protosolar-like nebulae: The molecular content of the DMTau and GGTau disks

A.Dutrey, S.Guilloteau, M.Guélin,
Institut de Radio Astronomie Millimétrique, 300 Rue de la Piscine, F-38406 Saint Martin d'Hères, France
Abstract: We report the detection of CN, HCN, HNC, CS, HCO tex2html_wrap_inline652 , C tex2html_wrap_inline626 H and H tex2html_wrap_inline626 CO (ortho and para) in the protoplanetary disks of DM Tau and GG Tau. For the first time organic molecules are observed in objects representative of the presolar nebula. These molecules are underabundant with respect to the standard dense clouds. The depletions in the ``outer'' disk of DM Tau (100<r<900 AU), derived from the line intensities and state of excitation, range from tex2html_wrap_inline660 (for CO) to 100 (for H tex2html_wrap_inline626 CO). The relatively large abundances of CN and C tex2html_wrap_inline626 H are typical of a photon-dominated chemistry (Figs. 1,  2).

Accepted for publications in A&A 317, L2

Figure: Line profiles observed toward GGTau. Integration time (on + off) is 4-8 h for each spectrum. Double-peaked profiles are observed for H tex2html_wrap_inline626 CO 3 tex2html_wrap_inline668 -2 tex2html_wrap_inline670 and CS 3-2 and 5-4. They agree in position and width with the CO line profiles. Hyperfine components of HCN and CN are indicated.

Figure: Same as Fig. 1, for DMTau.