Debris disks are second-generation circumstellar disks around main sequence stars. Their dust and gas are thought to be mostly produced by collisions of bodies that failed to grow into planets (planetesimals) and from cometary activity. While the dust content of these disks has been relatively well characterized, the amount of gas is still unknown in most disks.
In 2006 I used the Spitzer Space Telescope to establish that debris disks around relatively young stars (<30Myr) contain less than 1 Jupiter mass of gas. These results demonstrated that: i) giant planets must form early and ii) there is not enough gas at these stage to circularize the orbits of terrestrial planets. [Pascucci et al. 2006]
More recently I contributed to several papers using sensitive millimeter observations to set tighter limits on the gas mass in debris disks and refine the transition from protoplanetary to debris. A few of them are:
– Kóspál, Á. et al. 2013 “ALMA Observations of the Molecular Gas in the Debris Disk of the 30 Myr Old Star HD 21997”
– Moór, A. et al. 2015 (Discovery of Molecular Gas around HD 131835 in an APEX Molecular Line Survey of Bright Debris Disks), 2013 (ALMA Continuum Observations of a 30 Myr Old Gaseous Debris Disk around HD 21997), 2011 (Molecular Gas in Young Debris Disks)