Observations of HDO in the high-mass formation regions

Magda Kulczak-Jastrzębska, Dariusz Lis and Maryvonne Gerin

Deuterated species are powerful tools to study the physical structure and dynamics of protostellar envelopes, yet their observations are still scarce. We present observations of the ground state 1_0.1-0_0.0 rotational transition of HDO at 464.925 GHz and the 1_1.0-1_0.1 transition at 509.292 towards three high-mass star forming regions, carried out with the Caltech Submillimeter Observatory. The latter transition is observed for the first time from the ground. The HDO lines are modeled using a spherically symmetric radiative transfer code to derive the radial distribution of the HDO abundance in the target sources. The abundance profile is divided into an inner hot core region, with T > 100 K and a cold outer envelope with T< 100 K. The H₂¹⁸O observations from Flagey et al. (2013) are used to calculate the H₂O abundance profile and thus, allow us to constrain the HDO/H₂O ratio in the envelopes of high-mass star forming regions.

Proceedings of the Polish Astronomical Society, vol. 3, 195-199 (2016)

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