Year: 2019
Type: article
Abstract: Previous observations revealed the existence of CO gas at nearly protoplanetary level in several dust-rich debris disks around young A-type stars. Here we used the Atacama Large Millimeter/submillimeter Array (ALMA) 7 m Array to measure 13CO and C18O emission toward two debris disks, 49 Cet and HD 32297, and detected similarly high CO content (>0.01 M ⊕). These high CO masses imply a highly efficient shielding of CO molecules against stellar and interstellar ultraviolet photons. Adapting a recent secondary gas disk model that considers both shielding by carbon atoms and self-shielding of CO, we can explain the observed CO level in both systems. Based on the derived gas densities we suggest that, in the HD 32297 disk, dust and gas are coupled and the dynamics of small grains is affected by the gaseous component. For 49 Cet, the question of coupling remains undecided. We found that the main stellar and disk properties of 49 Cet and HD 32297 are very similar to those of previously identified debris disks with high CO content. These objects constitute together the first known representatives of shielded debris disks.
Source: The Astrophysical Journal
Authors: Attila Moór, Quentin Kral, Péter Ábrahám, Ágnes Kóspál, Anne Dutrey, Emmanuel Di Folco, A. Meredith Hughes, Attila Juhász, Ilaria Pascucci, Nicole Pawellek
Institutions: Konkoly Observatory, HUN-REN Research Centre for Astronomy and Earth Sciences, Hungarian Academy of Sciences, Centre National de la Recherche Scientifique, Université Paris Sciences et Lettres, Observatoire de Paris, Sorbonne Université, Sorbonne Paris Cité, Laboratoire d’études spatiales et d’instrumentation en astrophysique, Max Planck Institute for Astronomy, Université de Bordeaux, Laboratoire d'Astrophysique de Bordeaux, Wesleyan University, University of Cambridge, University of Arizona
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: bronze
Funders: National Science Foundation, National Radio Astronomy Observatory, European Space Agency, National Science Council, Hungarian Scientific Research Fund, Korea Astronomy and Space Science Institute, National Astronomical Observatory of Japan, Science and Technology Facilities Council, National Institutes of Natural Sciences
OpenAlex ID: W2969428277