Comet 67P/Churyumov-Gerasimenko radio spectra

In particular, the asymmetry of the line is well represented by a jet concentrating three-quarters of the outgassing in about pi steradians. We derived abundances relative to water for seven molecules and significant upper limits for approximately five others. The retrieved abundances were compared to those measured in situ at the previous perihelion with Rosetta.

While those of HCN, CH_3_OH, and HNCO are comparable, 67P is found to be depleted in H_2_S and relatively normal in CS (H_2_S/CS_3_) in strong contradiction with the Rosetta/ROSINA mass spectrometer measurement of the H_2_S/CS_2_ (~100) abundance ratio. While the formaldehyde total abundance found with IRAM~30-m when assuming it to be mostly produced by a distributed source (Haser parent scale length ~8000km) is similar to the one derived by Rosetta/ROSINA, we find that the formaldehyde coming from the nucleus is one order of magnitude less abundant than measured in situ by Rosetta/ROSINA.