Herschel Guaranteed Time Key Program "HIFI Spectral Surveys of Star Forming Regions”
(also called CHESS for "Chemical HErschel Surveys of Star forming regions")
(PI: Cecilia Ceccarelli, 281 hours allocated)
Study of the molecular content of regions far beyond our Solar System has advanced enormously during the last few decades, from the first detections of diatomic molecules to the discovery of polyatomic, complex organic molecules. Nowadays, one major goal of Astrochemistry is to have the most accurate census of the molecular content (and complexity) in Star Forming Regions (SFRs). In the era of the molecular content census, unbiased spectral surveys in the radio to Infrared of SFRs have become a fundamental and necessary tool in modern astrochemistry research. In this context, the frequency range covered by HSO-HIFI, 500-2000 GHz, is of particular importance. It is in this frequency range that light molecules have their ground and low energy transitions, whereas heavier molecules have higher energy transitions. The latter are excited in the warm gas, whereas the former probe the gas at low temperatures as well. It is therefore in the HIFI frequency range that the major gas coolants (notably H2O) and some key components of the chemical composition of SFRs emit. We propose to obtain Spectral Surveys in the HSO-HIFI range of a representative sample of SFRs. To have a meaningful coverage of the different evolutionary stages and different masses requires a large amount of time, about 300 hrs. The proposed observations will provide a large dataset of uttermost interest for the entire astronomical community, and, particularly for the study of star formation processes and of the influence of chemistry on star and planet formation. These two basic aspects, a large requested observing time and an output of high archival value, make the present proposal suitable for a HSO Key Program.
DOI linked publication: http://doi.org/10.5281/zenodo.4596919