New Millimeter CO Observations of the Gas-rich Debris Disks 49 Cet and HD32297

0539882 - ASÚ 2021 RIV US eng J - Journal Article
Moór, A. … Total 10 authors
New Millimeter CO Observations of the Gas-rich Debris Disks 49 Cet and HD32297.
Astrophysical Journal. Roč. 884, č. 2 (2019), č. článku 108. ISSN 0004-637X. E-ISSN 1538-4357
Research Infrastructure: EU-ARC.CZ - 90067
Keywords : beta-pictoris * molecular-hydrogen * exocometary gas
OECD category: Astronomy (including astrophysics,space science)
Impact factor: 5.746, year: 2019
Method of publishing: Limited access
https://doi.org/10.3847/1538-4357/ab4272

We used the Atacama Large Millimeter/submillimeter Array (ALMA) 7m Array to measure (CO)-C-13 and (CO)-O-18 emission toward two debris disks, 49 Cet and HD 32297, and detected similarly high CO content (>0.01 M-circle plus). 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.
Permanent Link: http://hdl.handle.net/11104/0317578