We propose the first extensive, systematic survey of gas in circumstellar disks over the critical transition from gas-rich protoplanetary through to gas-poor debris system. The brightest spectral lines from disks lie in the far-infrared and arise from radii virgul10-500 AU, where giant planets are expected to form. Herschel is uniquely able to observe this wavelength regime with the sensitivity to allow a large scale survey.
We will carry out a 2-phase PACS study, surveying the fine structure lines of [CII]157um and [OI]63um in 274 objects, and following up the brightest sources with observations of H2O and [OI]145um. The gas mass sensitivity, a few 1e-5 Msun, will be more than an order of magnitude lower than achieved by ISO and Spitzer and expected for SOFIA. We will also measure the dust continuum to an equivalent mass sensitivity. Team members include experts in the modeling of disk structure, chemistry, and radiative transfer necessary to interpret these data.
We will observe nearby clusters in the age range 1-30Myr, encompassing disk masses 1e-2 - 1e-5 Msun, and stellar luminosity 1-100 Lsun. This covers the dominant epoch of planet formation and the mass from protoplanetary through to young debris disk. Furthermore our sample is chosen to include a wide range of X-ray & UV flux, and SED shape, from classical SED Class II, through transition disks with inner dust holes, to disks with small IR excesses. With this extensive dataset, our program will:
- Trace gas and dust in the planet formation region across an extensive multivariate parameter space
- Provide the first definitive measurement of the gas dissipation timescale in disks
- Study the evolutionary link between protoplanetary and debris disks
- Investigate the extent and evolution of warm H2O in the planet-forming re...gions of disks, with implications for the volatile content of developing planets
- Provide an extensive database of disk observations and models with long-lasting legacy value for followup observations
Publication
GASPS—A Herschel Survey of Gas and Dust in Protoplanetary Disks: Summary and Initial Statistics . Dent W. R. F. et al. . Publications of the Astronomical Society of the Pacific, Volume 125, Issue 927, pp. 477-505 (2013). . 125 . 10.1086\/670826 . 2013PASP..125..477D , Debris Disk Results from the Gemini Planet Imager Exoplanet Survey.s Polarimetric Imaging Campaign . Esposito Thomas M. et al. . The Astronomical Journal . null . null . 2020AJ....160...24E , The SHARDDS survey: limits on planet occurrence rates based on point sources analysis via the Auto-RSM framework . Dahlqvist C. -H. et al. . Astronomy and Astrophysics . null . null . 2022A&A...666A..33D , A ∼75 per cent occurrence rate of debris discs around F stars in the β Pic moving group . Pawellek Nicole et al. . Monthly Notices of the Royal Astronomical Society . null . null . 2021MNRAS.502.5390P , Gas and dust in the beta Pictoris moving group as seen by the Herschel Space Observatory . Riviere-Marichalar P. et al. . Astronomy & Astrophysics, Volume 565, id.A68, 11 pp. . 565 . 10.1051\/0004-6361\/201322901 . 2014A&A...565A..68R ,
Herschel was launched on 14 May 2009! It is the fourth 'cornerstone' mission in the ESA science programme. With a 3.5 m Cassegrain telescope it is the largest space telescope ever launched. It is performing photometry and spectroscopy in approximately the 55-671 µm range, bridging the gap between earlier infrared space missions and groundbased facilities.
European Space Agency, 2013, Gas In Protoplanetary Systems. Openpargaspsclosepar, SPG v14.2.0, European Space Agency, https://doi.org/10.5270/esa-s2nq1s1
