A Surface Density Perturbation in the TW Hydrae Disk at 95 au Traced by Molecular Emission

Abstract : We present ALMA Cycle 2 observations at 0.″5 resolution of TW Hya of CS J=5-4 emission. The radial profile of the integrated line emission displays oscillatory features outward of 1.″5 (≈ 90 au). A dip-like feature at 1.″6 is coincident in location, depth, and width with features observed in dust scattered light at near-infrared wavelengths. Using a thermochemical model indicative of TW Hya, gas-grain chemical modeling, and non-LTE radiative transfer, we demonstrate that such a feature can be reproduced with a surface density depression, consistent with the modeling performed for scattered-light observations of TW Hya. We further demonstrate that a gap in the dust distribution and dust opacity only cannot reproduce the observed CS feature. The outer enhancement at 3.″1 is identified as a region of intensified desorption due to enhanced penetration of the interstellar far-UV radiation at the exponential edge of the disk surface density, which intensifies the photochemical processing of gas and ices.
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The Astrophysical journal letters, Bristol : IOP Publishing, 2017, 835 (2), pp.id. 228. 〈10.3847/1538-4357/835/2/228〉
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https://hal.archives-ouvertes.fr/hal-01462872
Contributeur : Marie-Paule Pomies <>
Soumis le : jeudi 9 février 2017 - 09:59:26
Dernière modification le : vendredi 10 février 2017 - 01:07:08

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R. Teague, D. Semenov, U. Gorti, S. Guilloteau, Th. Henning, et al.. A Surface Density Perturbation in the TW Hydrae Disk at 95 au Traced by Molecular Emission. The Astrophysical journal letters, Bristol : IOP Publishing, 2017, 835 (2), pp.id. 228. 〈10.3847/1538-4357/835/2/228〉. 〈hal-01462872〉

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