Ring structure in the MWC 480 disk revealed by ALMA^★

¹ Max Planck Institute for Astronomy, Königstuhl 17, 69117 Heidelberg, Germany
² Purple Mountain Observatory & Key Laboratory for Radio Astronomy, Chinese Academy of Sciences, 2 West Beijing Road, Nanjing 210008, PR China
e-mail: yliu@pmo.ac.cn
³ Department of Physics and Astronomy, University of Leicester, Leicester LE1 7RH, UK
⁴ Dipartimento di Fisica, Università Degli Studi di Milano, Via Celoria, 16, Milano, 20133, Italy
⁵ Kavli Institute for Astronomy and Astrophysics, Peking University, Yiheyuan 5, Haidian Qu, 100871 Beijing, PR China
⁶ Leiden Observatory, Leiden University, PO Box 9513, 2300 RA Leiden, The Netherlands
⁷ Rice University, Department of Physics and Astronomy, Main Street, 77005 Houston, USA
⁸ Université Grenoble Alpes, CNRS, IPAG, 38000 Grenoble, France
⁹ NRC Herzberg Astronomy and Astrophysics, 5071 West Saanich Road, Victoria, BC, V9E 2E7, Canada
¹⁰ Department of Physics and Astronomy, University of Victoria, Victoria, BC, V8P 5C2, Canada
¹¹ Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ 85721, USA
¹² Earths in Other Solar Systems Team, NASA Nexus for Exoplanet System Science, USA
¹³ Department of Astronomy/Steward Observatory, The University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721, USA
¹⁴ Vassar College Physics and Astronomy Department, 124 Raymond Avenue, Poughkeepsie, NY 12604, USA
¹⁵ Sorbonne Université, Observatoire de Paris, Université PSL, CNRS, LERMA, 75014 Paris, France
¹⁶ Space Telescope Science Institute Baltimore, MD 21218, USA
¹⁷ European Southern Observatory, Karl-Schwarzschild-Str. 2, 85748 Garching bei München, Germany
¹⁸ INAF-Osservatorio Astronomico di Roma, Via di Frascati 33, 00040 Monte Porzio Catone, Italy
¹⁹ INAF-Osservatorio Astronomico di Padova, Vicolo dell’Osservatorio 5, 35122 Padova, Italy
²⁰ NASA Ames Research Center and Bay Area Environmental Research Institute, Moffett Field, CA 94035, USA

Received: 29 August 2018
Accepted: 8 November 2018

Abstract

Gap-like structures in protoplanetary disks are likely related to planet formation processes. In this paper, we present and analyze high-resolution (0.17′′× 0.11′′) 1.3 mm ALMA continuum observations of the protoplanetary disk around the Herbig Ae star MWC 480. Our observations show for the first time a gap centered at ~74 au with a width of ~23 au, surrounded by a bright ring centered at ~98 au from the central star. Detailed radiative transfer modeling of the ALMA image and the broadband spectral energy distribution is used to constrain the surface density profile and structural parameters of the disk. If the width of the gap corresponds to 4–8 times the Hill radius of a single forming planet, then the putative planet would have a mass of 0.4–3 M_J. We test this prediction by performing global three-dimensional smoothed particle hydrodynamic gas/dust simulations of disks hosting a migrating and accreting planet. We find that the dust emission across the disk is consistent with the presence of an embedded planet with a mass of ~2.3 M_J at an orbital radius of ~78 au. Given the surface density of the best-fit radiative transfer model, the amount of depleted mass in the gap is higher than the mass of the putative planet, which satisfies the basic condition for the formation of such a planet.