Subproject B3: The chemical evolution from diffuse clouds to dense cores
Henrik Beuther (MPIA), Cornelis Dullemond (ITA)
Theoretical and observational multi-spatial-scale study of the chemistry within the ISM, including the evolution of complex molecules from the low-density molecular clouds to high-density star-forming regions, of fractional ionization of the ISM, and of the chemistry as a function of Galactocentric distance.
More than 180 molecules have been detected in the ISM, in young massive star-forming regions, and in circumstellar shells. Although less abundant than H2, many of these molecules play crucial roles in the Galactic ISM matter cycle. In the first funding period, we investigated observationally and theoretically the chemical properties and evolution of molecular clouds all the way to the onset of massive star formation and further to protostellar objects and finally ultracompact HII regions (see also subproject B2). The observational sample covered all the different stages of this evolutionary process. Chemical abundances were derived for the different stages, accompanied by sophisticated chemical evolution modeling. An innovative way of introducing tracer particles into the models was developed, although the successful implementation took longer than expected. Furthermore, substantial progress was made in understanding isotopic species such as deuterated molecules and the 13CO/12CO ratio.
Gerner, T., Beuther H., Semenov, D., Linz, H. Vasyunina T., Bihr S., Shirley, Y.L., Henning, Th.: The chemical evolution in the early phases of massive star formation, A&A in press, arXiv: 1401.6382v1 (2014)
Szucs, L., Glover, S.C.O., Klessen, R.S.: The 12CO/ 13CO ratio in turbulent molecular clouds, MNRAS, submitted; arXiv: 1403.4912 (2014)