Chemistry in Disks VIII: the CS molecule as an analytic tracer of turbulence in disks

S. Guilloteau 1 Anne Dutrey 1 Valentine Wakelam 1 F. Hersant 2 D. Semenov 3 E. Chapillon 4, 1 T. Henning 3 V. Piétu 5
1 AMOR 2012
L3AB - Laboratoire d'astrodynamique, d'astrophysique et d'aéronomie de bordeaux, OASU - Observatoire aquitain des sciences de l'univers, LAB - Laboratoire d'Astrophysique de Bordeaux [Pessac], Université Sciences et Technologies - Bordeaux 1
2 FORMATION STELLAIRE 2012
L3AB - Laboratoire d'astrodynamique, d'astrophysique et d'aéronomie de bordeaux, OASU - Observatoire aquitain des sciences de l'univers, LAB - Laboratoire d'Astrophysique de Bordeaux [Pessac], Université Sciences et Technologies - Bordeaux 1
Abstract : Turbulence is thought to be a key driver of the evolution of protoplanetary disks, regulating the mass accretion process, the transport of angular momentum, and the growth of dust particles. We intend to determine the magnitude of the turbulent motions in the outer parts (> 100 AU) of the disk surrounding DM Tau. Turbulent motions can be constrained by measuring the nonthermal broadening of line emission from heavy molecules. We used the IRAM Plateau de Bure interferometer to study emission from the CS molecule in the disk of DM Tau. High spatial (1.4 x 1 ") and spectral resolution (0.126 km/s) CS J=3-2 images provide constraints on the molecule distribution and velocity structure of the disk. A low sensitivity CS J=5-4 image was used in conjunction to evaluate the excitation conditions. We analyzed the data in terms of two parametric disk models, and compared the results with detailed time-dependent chemical simulations. The CS data confirm the relatively low temperature suggested by observations of other simple molecules. The intrinsic linewidth derived from the CS J=3-2 data is much larger than expected from pure thermal broadening. The magnitude of the derived nonthermal component depends only weakly on assumptions about the location of the CS molecules with respect to the disk plane. Our results indicate turbulence with a Mach number around 0.4 - 0.5 in the molecular layer. Geometrical constraints suggest that this layer is located near one scale height, in reasonable agreement with chemical model predictions.
Liste complète des métadonnées

https://hal.archives-ouvertes.fr/hal-00764159
Contributeur : Marie-Paule Pomies <>
Soumis le : mercredi 12 décembre 2012 - 14:47:13
Dernière modification le : mercredi 27 juillet 2016 - 14:48:48

Identifiants

Collections

Citation

S. Guilloteau, Anne Dutrey, Valentine Wakelam, F. Hersant, D. Semenov, et al.. Chemistry in Disks VIII: the CS molecule as an analytic tracer of turbulence in disks. Astronomy and Astrophysics - A&A, EDP Sciences, 2012, 548, pp.id.A70. <10.1051/0004-6361/201220331>. <hal-00764159>

Partager

Métriques

Consultations de la notice

145