Resolved millimeter-dust continuum cavity around the very low mass young star CIDA 1

Context. Transition disks (TDs) are circumstellar disks with inner regions highly depleted in dust. TDs are observed in a small fraction of disk-bearing objects at ages of 1-10 Myr. They are important laboratories to study evolutionary effects in disks, from photoevaporation to planet-disk interactions. Aim. We report the discovery of a large inner dust-empty region in the disk around the very low mass star CIDA 1 (M-* similar to 0.1-0.2 M-circle dot). Methods. We used ALMA continuum observations at 887 mu m, which provide a spatial resolution of 0.'' 21 x 0.'' 12(similar to 15 x 8 au in radius at 140 pc). Results. The data show a dusty ring with a clear cavity of radius similar to 20 au, the typical characteristic of a TD. The emission in the ring is well described by a narrow Gaussian profile. The dust mass in the disk is similar to 17 M-circle plus. CIDA 1 is one of the lowest mass stars with a clearly detected millimeter cavity. When compared to objects of similar stellar mass, it has a relatively massive dusty disk (less than similar to 5% of Taurus Class II disks in Taurus have a ratio of M-disk/M-* larger than CIDA 1) and a very high mass accretion rate (CIDA 1 is a disk with one of the lowest values of M-disk/(M) over dot ever observed). In light of these unusual parameters, we discuss a number of possible mechanisms that can be responsible for the formation of the dust cavity (e.g. photoevaporation, dead zones, embedded planets, close binary). We find that an embedded planet of a Saturn mass or a close binary are the most likely possibilities.NASA through Hubble Fellowship grant - Space Telescope Science Institute [HST-HF2-51380.001-A]; Association of Universities for Research in Astronomy, Inc. [NAS 5-26555]; Italian Ministero dell'Istruzione, Universita e Ricerca through the grant Progetti Premiali 2012 - iALMA [CUP C52I13000140001]; Deutsche Forschungs-Gemeinschaft (DFG, German Research Foundation) [FOR 2634/1 TE 1024/1-1]; DFG cluster of excellence Origin and Structure of the Universe; ERC [743029 EASY]; ESO FellowshipOpen access journal.This item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at repository@u.library.arizona.edu