Lab measurements for C-cyanomethanimine

For both the Z and E isomers, the spectroscopic work has led to an improved and extended knowledge of the spectroscopic parameters, thus providing accurate predictions of the rotational signatures up to ~700GHz. So far, no C-cyanomethanimine emission has been detected towards the ASAI targets, and upper limits on the column density of 10^11^-10^12^cm^-2^ could only be derived. Consequently, the C-cyanomethanimine abundances have to be less than a few 10^-10^ for starless and hot-corinos.

A less stringent constraint, <=10^-9^, is obtained for shocks sites. The combination of the upper limits on the abundances of C-cyanomethanimine together with accurate laboratory frequencies up to ~700GHz poses the basis for future higher sensitivity searches around Sun-like star forming regions. For compact (typically less than 1 arcsec) and chemically enriched sources such as hot-corinos, the use of interferometers as NOEMA and ALMA in their extended configurations are clearly needed.