Protostars and Planets VI, Heidelberg, July 15-20, 2013

Poster 2H001

Planet formation in action: Resolved gas and dust images of a transitional disk and its cavity

van der Marel, Nienke (Leiden Observatory, Leiden, the Netherlands)
van Dishoeck, Ewine (Leiden Observatory, Leiden, the Netherlands; MPE, Garching, Germany)
Bruderer, Simon (MPE, Garching, Germany)
Birnstiel, Til (CfA, Boston, USA)
Pinilla, Paola (ITA Heidelberg, Heidelberg, Germany)
Dullemond, Cornelis (ITA Heidelberg, Heidelberg, Germany)
van Kempen, Tim (Leiden Observatory, Leiden, the Netherlands; JAO, Santiago, Chile)
Schmalzl, Markus (Leiden Observatory, Leiden, the Netherlands)
Brown, Joanna (CfA, Boston, USA)
Herczeg, Gregory (Beijing University, Beijing, China)
Mathews, Geoffrey (Leiden Observatory, Leiden, the Netherlands)
Geers, Vincent (DIAS, Dublin, Ireland)

Planet formation and clearing of protoplanetary disks is one of the long standing problems in disk evolution theory. The best test of clearing scenarios is observing systems that are most likely to be actively forming planets: the transitional disks with large inner dust cavities. We present the first results of our ALMA Cycle 0 program using Band 9, imaging the Herbig Ae star Oph IRS 48 in CO 6–5, C17O 6–5 and the submillimeter continuum in the extended configuration. The resulting ∼0.2” spatial resolution completely resolves the cavity of this disk in the gas and the dust. The huge leap in sensitivity provided by ALMA at high frequencies allows a large dynamic range of gas masses inside the dust cavity to be tested. The gas cavity of IRS 48 is only half as large as the dust cavity and the gas surface density inside this gas cavity is at least two orders of magnitude lower than the gas in the surrounding ring. On the other hand, the continuum emission reveals an unexpected huge asymmetry and steep edges in the dust distribution along the ring suggestive of dust trapping. We will discuss the implications of the combined gas and dust distribution for planet formation at a very early stage. This is the first transitional disk with spatially resolved gas inside the cavity, demonstrating the superb capabilities of the Band 9 receivers.

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