Millimeter/submillimeter Observations of Molecules in Disks
Résumé
In the late nineties, upgrades of Mm/submm arrays allowed observers to map molecular disks orbiting around young low and intermediate mass stars (M < 3-5 MSun). In these disks of a few million year old most of the mass is the form of molecular hydrogen. Understanding their chemistry and physics is of prime importance since they are expected to be the sites of planet formation. So far, low rotational lines of molecular ions and molecules such as CO and isotopologues, CN, HCN, CS, H2CO, HCO+, N2H+ ... were imaged in a few objects. Although the sensitivity remains the major limitation, these observations provide not only new inputs for chemistry models but also a better knowledge of the disk physical structure. In these objects, the existence of relatively large temperature and density gradients on short spatial scales implies that a good knowledge of the disk physical structure is needed to properly interpret the molecular observations and to understand its chemical behaviour. I will review these new observations and show how they give us some interesting tracks to explore with ALMA.