A surface density perturbation in the TW hydrae disk at 95 au traced by molecular emission

Journal Article · Wed Feb 01 04:00:00 EST 2017 · Astrophysical Journal

DOI:https://doi.org/10.3847/1538-4357/835/2/228· OSTI ID:22869442

Teague, R.; Semenov, D.; Henning, Th.; Birnstiel, T.; Boekel, R. van ^[1]; Gorti, U. ^[2]; Guilloteau, S.; Dutrey, A.

---

1. Max-Planck-Institut für Astronomie, Königstuhl 17, D-69117 Heidelberg (Germany)
2. NASA Ames Research Center, Moffett Field, CA 94035 (United States)

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.

• OSTI ID: 22869442
• Journal Information: Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 2 Vol. 835; ISSN ASJOAB; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
COMPUTERIZED SIMULATION
COSMIC DUST
DENSITY
DESORPTION
DISTRIBUTION
DISTURBANCES
EMISSION
MOLECULES
OPACITY
PERTURBATION THEORY
PHOTOCHEMISTRY
PROTOPLANETS
RADIANT HEAT TRANSFER
ULTRAVIOLET RADIATION