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

Poster 2B067

MOLECULAR GAS IN YOUNG DEBRIS DISKS

Moór, Attila (Konkoly Observatory, Hungary)
Kóspál, Ágnes (European Space Agency, The Netherlands)
Ábrahám, Péter (Konkoly Observatory, Hungary)
Juhász, Attila (Leiden Observatory, The Netherlands)
Apai, Dániel (Dept. of Astronomy and Dept. of Planetary Sciences, Univ. Arizona, USA)
Csengeri, Timea (Max-Planck-Institut für Radioastronomie, Germany)
Grady, Carol (Eureka Scientific and NASA GSFC, USA)
Henning, Thomas (Max-Planck-Institut für Astronomie, Germany)
Kiss, Csaba (Konkoly Observatory, Hungary)
Pascucci, Ilaria (Dept. of Astronomy and Dept. of Planetary Sciences, Univ. Arizona, USA)

Abstract:
Gas-rich primordial disks and tenuous gas-poor debris disks are usually considered as two distinct evolutionary phases of the circumstellar matter. So far only a very few debris disks with measurable gas component have been known. We carried out a survey with the APEX radio telescope to detect molecular gas at millimeter wavelengths in 28 infrared-luminous young debris disks, and discovered two new systems with substantial amount of CO. Motivated to understand the origin, physics, and evolutionary status of the gas in these systems we observed one of them, HD 21997, with ALMA and Herschel. Our results suggest that HD 21997 may be a hybrid system where secondary debris dust and residual primordial gas coexist. This poses a serious question to the current paradigm, since the age of the system (30 Myr) significantly exceeds model predictions for disk clearing and the ages of the oldest transitional disks.

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