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Title: Herschel evidence for disk flattening or gas depletion in transitional disks

Transitional disks are protoplanetary disks characterized by reduced near- and mid-infrared emission, with respect to full disks. This characteristic spectral energy distribution indicates the presence of an optically thin inner cavity within the dust disk believed to mark the disappearance of the primordial massive disk. We present new Herschel Space Observatory PACS spectra of [O I] 63.18 μm for 21 transitional disks. Our survey complements the larger Herschel GASPS program ({sup G}as in Protoplanetary Systems{sup )} by quadrupling the number of transitional disks observed with PACS in this wavelength. [O I] 63.18 μm traces material in the outer regions of the disk, beyond the inner cavity of most transitional disks. We find that transitional disks have [O I] 63.18 μm line luminosities ∼2 times fainter than their full disk counterparts. We self-consistently determine various stellar properties (e.g., bolometric luminosity, FUV excess, etc.) and disk properties (e.g., disk dust mass, etc.) that could influence the [O I] 63.18 μm line luminosity, and we find no correlations that can explain the lower [O I] 63.18 μm line luminosities in transitional disks. Using a grid of thermo-chemical protoplanetary disk models, we conclude that either transitional disks are less flared than full disks ormore » they possess lower gas-to-dust ratios due to a depletion of gas mass. This result suggests that transitional disks are more evolved than their full disk counterparts, possibly even at large radii.« less
Authors:
;  [1] ;  [2] ;  [3] ;  [4] ;  [5] ;  [6] ;  [7] ;  [8]
  1. Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ 85721 (United States)
  2. Department of Astronomy, Boston University, Boston, MA 02215 (United States)
  3. SUPA, School of Physics and Astronomy, University of St. Andrews, North Haugh, St. Andrews KY16 9SS (United Kingdom)
  4. Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138 (United States)
  5. Kapteyn Astronomical Institute, Postbus 800, 9700 AV Groningen (Netherlands)
  6. Institut de Planétologie et d'Astrophysique (IPAG) UMR 5274, Université Joseph Fourier Grenoble-1, CNRS-INSU, F-38041 Grenoble (France)
  7. Departamento de Física Teórica, Universidad Autónoma de Madrid, Campus Cantoblanco, E-28049 Madrid (Spain)
  8. ALMA SCO, Alonso de Cordova 3107, Vitacura, Santiago (Chile)
Publication Date:
OSTI Identifier:
22356746
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 787; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ACCRETION DISKS; BOLOMETERS; DUSTS; EMISSION; ENERGY SPECTRA; FAR ULTRAVIOLET RADIATION; LUMINOSITY; MASS; PERTURBED ANGULAR CORRELATION; PROTOPLANETS; SPACE; STARS