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This paper will review the basic concepts of gas-phase and grain surface chemistry of dense molecular clouds, where low mass and high mass stars form. The chemistry of cold pre-stellar cloud cores, where molecular freeze-out and deuterium fractionation dominate, will be presented. Then, following cloud evolution after protostellar birth, hot core and shock chemistry will be discussed in view of recent observations. A brief summary of the chemistry in protoplanetary disks will also be furnished. The aim is to identify important gas tracers in the various steps of the star formation process, pointing out the main problems still open in the field of astrochemistry.
Maser emission plays an important role as a tool in star formation studies. It is widely used for deriving kinematics, as well as the physical conditions of different structures, hidden in the dense environment very close to the young stars, for exam
The chemical changes of high-mass star-forming regions provide a potential method for classifying their evolutionary stages and, ultimately, ages. In this study, we search for correlations between molecular abundances and the evolutionary stages of d
The determination of accurate distances to star-forming regions are discussed in the broader historical context of astronomical distance measurements. We summarize recent results for regions within 1 kpc and present perspectives for the near and more distance future.
We present a theoretical study of the deuterated species detectability in various types of extragalactic star-forming regions based on our predictions of chemical abundances. This work is motivated by the past and current attempts at observing deuter
An overview is given of the analysis of more than a decade of H2O maser data from our monitoring program. We find the maser emission to generally depend on the luminosity of the YSO as well as on the geometry of the SFR. There appears to be a thresho