Friday, 9th March at 2.00pm at the JAC

ABSTRACT: In the last decade various deuterated molecules have been detected in space. Chemical models identified H2D+ and higher deuterated isotopologues to be one of the key molecules in the formation of most deuterated molecules. Unfortunately, there are only very few observations of these key molecules, because of the low atmospheric transmission at the frequencies of the ortho-H2D+ and para-D2H+ ground-state transition. Instead N2D+ can often be used as an easily observable tracer of H2D+. In this talk I will present my N2D+ and N2H+ observations of Class 0 protostars. Comparisons of the N2D+/N2H+ ratio with evolutionary tracers, such as dust temperature, indicate a tight correlation of deuterium fractionation with age.

In very cold environments, however, it is not unlikely that N2D+ freezes out and observations of H2D+ or D2H+ become unavoidable. For a full account of H2D+ and higher deuterated isotopologues both the ortho and the para transitions have to be observed. The para-H2D+ and ortho-D2H+ ground-state transition are at 1.37 and 1.48 THz, respectively. For those observations (as well as for observations of high-J CO transitions and N+) we have built CONDOR, a 1.2 to 1.5 THz heterodyne receiver. In the talk I will give a short introduction to this receiver and its first observations from APEX, which have so far focussed on the warm gas in high mass star forming regions observed in CO 13-12.

Relevant web site:
CONDOR the 1.4 THz Receiver

Related Paper:
Wiedner et al. 2006, A&A, 454, 33
Crapsi et al. 2005, ApJ, 619, 379