ALMA observations of a small sample of transitional disks with large dust cavities observed in Cycle 0 and 1 are summarized. The gas and dust surface density structures are inferred from the continuum and 12CO, 13CO and C18O line data using the DALI physical-chemical code. Thanks to its ability to self-shield, CO can survive inside dust cavities in spite of being exposed to intense UV radiation and can thus be used as a probe of the gas structure. Modeling of the existing data shows that gas is present inside the dust cavities in all cases, but at a reduced level compared with the gas surface density profile of the outer disk. The gas density decrease inside the dust cavity radius by factors of up to 10^4 suggests clearing by one or more planetary-mass companions. The accompanying pressure bumps naturally lead to trapping of the mm-sized dust grains observed in the ALMA images.
@article{arxiv.1505.01947,
title = {Quantifying the gas inside dust cavities in transitional disks: implications for young planets},
author = {E. F. van Dishoeck and N. van der Marel and S. Bruderer and P. Pinilla},
journal= {arXiv preprint arXiv:1505.01947},
year = {2015}
}
Comments
4 pages, 2 figures; dd. March 18 2015. To appear in "Revolution in Astronomy with ALMA: the 3rd year", 2015, ed. D. Iono et al. (ASP conference series)