Status Report

ALMA unveils rings and gaps in the protoplanetary system HD 169142: signatures of two giant protoplanets

By SpaceRef Editor
February 14, 2017
Filed under , ,

D. Fedele (1), M. Carney (2), M. R. Hogerheijde (2), C. Walsh (2, 3), A. Miotello (2), P. Klaassen (4), S. Bruderer (5), Th. Henning (6), E.F. vanDishoeck (2 and 5) ((1) INAF-Osservatorio Astrofisico di Arcetri (2) Leiden Observatory, Leiden University (3) School of Physics and Astronomy, University of Leeds (4) UK Astronomy Technology Centre, Royal Observatory Edinburgh (5) Max Planck Institut für Extraterrestrische Physik (6) Max-Planck-Institute for Astronomy)
(Submitted on 9 Feb 2017)

The protoplanetary system HD 169142 is one of the few cases where a potential candidate protoplanet has been recently detected via direct imaging. To study the interaction between the protoplanet and the disk itself observations of the gas and dust surface density structure are needed. This paper reports new ALMA observations of the dust continuum at 1.3\,mm, 12CO, 13CO and C18O J=2−1 emission from the system HD 169142 at angular resolution of ∼0″.18−0″.28 (∼20au−33au). The dust continuum emission reveals a double-ring structure with an inner ring between 0″.17−0″.28 (∼20−35au) and an outer ring between 0″.48−0″.64 (∼56−83au). The size and position of the inner ring is in good agreement with previous polarimetric observations in the near-infrared and is consistent with dust trapping by a massive planet. No dust emission is detected inside the inner dust cavity (R≲20au) or within the dust gap (∼35−56au). In contrast, the channel maps of the J=2−1 line of the three CO isotopologues reveal the presence of gas inside the dust cavity and dust gap. The gaseous disk is also much larger than the compact dust emission extending to ∼1′.5 (∼180au) in radius. This difference and the sharp drop of the continuum emission at large radii point to radial drift of large dust grains (> \micron-size). Using the thermo-chemical disk code \textsc{dali}, the continuum and the CO isotopologues emission are modelled to quantitatively measure the gas and dust surface densities. The resulting gas surface density is reduced by a factor of ∼30−40 inward of the dust gap. The gas and dust distribution hint at the presence of multiple planets shaping the disk structure via dynamical clearing (dust cavity and gap) and dust trapping (double ring dust distribution).

Comments:    Accepted for publication in A&A
Subjects:    Solar and Stellar Astrophysics (astro-ph.SR); Earth and Planetary Astrophysics (astro-ph.EP); Astrophysics of Galaxies (astro-ph.GA)
Cite as:    arXiv:1702.02844 [astro-ph.SR] (or arXiv:1702.02844v1 [astro-ph.SR] for this version)
Submission history
From: Davide Fedele 
[v1] Thu, 9 Feb 2017 14:26:39 GMT (8000kb,D)

SpaceRef staff editor.