Gas Cavities inside Dust Cavities in Disks Inferred from ALMA Observations. Issue Volume 10:Issue S314(2015) (November 2015)

• Record Type: Journal Article
• Authors: van der Marel, Nienke; van Dishoeck, Ewine F.; Bruderer, Simon; Pinilla, Paola; van Kempen, Tim; Perez, Laura; Isella, Andrea
• Editors: Kastner, J. H.; Stelzer, B.; Metchev, S. A.
• Is Part Of: Proceedings of the International Astronomical Union. Volume 10:Issue S314(2015)
• Page Start: 139
• Page End: 142
• Publication Date: 2015-11
• Subjects: planetary systems: formation, -- planetary systems: protoplanetary disks, -- techniques: interferometric, -- molecular data, -- radiative transfer; Astronomy -- Congresses; Astronomy -- Periodicals; 520
• DOI: 10.1017/S1743921315006444
• Languages: English
• ISSNs: 1743-9213

Abstract

Abstract: Protoplanetary disks with cavities in their dust distribution, also named transitional disks, are expected to be in the middle of active evolution and possibly planet formation. In recent years, millimeter-dust rings observed by ALMA have been suggested to have their origin in dust traps, caused by pressure bumps. One of the ways to generate these is by the presence of planets, which lower the gas density along their orbit and create pressure bumps at the edge. We present spatially resolved ALMA Cycle 0 and Cycle 1 observations of CO and CO isotopologues of several famous transitional disks. Gas is found to be present inside the dust cavities, but at a reduced level compared with the gas surface density profile of the outer disk. The dust and gas emission are quantified using the physical-chemical modeling code DALI. In the majority of these disks we find clear evidence for a drop in gas density of at least a factor of 10 inside the cavity, whereas the dust density drops by at least a factor 1000. The CO isotopologue observations reveal that the gas cavities are significantly smaller than the dust cavities. These gas structures suggest clearing by one or more planetary-mass companions.