An 80 au cavity in the disk around HD 34282

¹ Univ. Grenoble Alpes, CNRS, IPAG (UMR 5274), 38000 Grenoble, France
e-mail: info@gerritvanderplas.com
² Departamento de Astronomía, Universidad de Chile, Casilla 36-D, Santiago, Chile
³ Departamento de Física Teórica, Universidad Autónoma de Madrid, Cantoblanco, 28049 Madrid, Spain
⁴ ETH Zurich, Institute for Astronomy, Wolfgang-PauliStrasse 27, 8093 Zurich, Switzerland
⁵ Millenium Nucleus Protoplanetary Disks in ALMA Early Science, Universidad de Chile, Casilla 36-D, Santiago, Chile
⁶ Departamento de Ciencias Físicas, Facultad de Ciencias Exactas, Universidad Andrés Bello, Av. Fernàndez Concha 700, Las Condes, Santiago, Chile
⁷ Nucleo de Astronomia, Facultad de Ingeniería, Universidad Diego Portales, Av. Ejércíto 441, Santiago, Chile

Received: 18 June 2017
Accepted: 5 July 2017

Abstract

Context. Large cavities in disks are important testing grounds for the mechanisms proposed to drive disk evolution and dispersion, such as dynamical clearing by planets and photoevaporation.

Aims. We aim to resolve the large cavity in the disk around HD 34282, whose presence has been predicted by previous studies modeling the spectral energy distribution of the disk.

Methods. Using ALMA band 7 observations we studied HD 34282 with a spatial resolution of 0.10″ × 0.17′′ at 345 GHz.

Results. We resolve the disk around HD 34282 into a ring between 0.24′′ and 1.15′′ (78⁺⁷_-11 and 374⁺³³_-54 au adopting a distance of 325⁺²⁹_-47 pc). The emission in this ring shows azimuthal asymmetry centered at a radial distance of 0.46′′ and a position angle of 135° and an azimuthal FWHM of 51°. We detect CO emission both inside the disk cavity and as far out as 2.7 times the radial extent of the dust emission.

Conclusions. Both the large disk cavity and the azimuthal structure in the disk around HD 34282 can be explained by the presence of a 50 M_jup brown dwarf companion at a separation of ≈0.1′′.