Deuterium Fractionation Survey Toward Protostellar Sources in the Perseus Molecular Cloud: HNC Case

Muneaki Imai , Nami Sakai , Ana López-Sepulcre , Aya E. Higuchi , Yichen Zhang , Yoko Oya , Yoshimasa Watanabe , Takeshi Sakai , Cecilia Ceccarelli (1) , Bertrand Lefloch (1) , Satoshi Yamamoto

1 IPAG - Institut de Planétologie et d'Astrophysique de Grenoble

A survey observation of the DNC (J = 1-0 and J = 3-2) and HN¹³C (J = 1-0 and J = 3-2) emission toward 34 Class 0 and I protostellar sources in the Perseus molecular cloud has been conducted with the NRO 45 m and IRAM 30 m telescopes to explore how the deuterium ratio of the neutral species changes after the birth of a protostar. We have detected the J = 1-0 and J = 3-2 lines of DNC toward 32 sources and the J = 1-0 and J = 3-2 lines of HN¹³C toward 31 and 26 sources, respectively. A mean deuterium ratio of HNC, which is defined as R _D(HNC) = N(DNC)/N(HNC), is found to be 0.049-0.056. We compare R _D(HNC) with physical parameters of the sources, and find a negative correlation between R _D(HNC) and the bolometric temperature. This result suggests that R _D(HNC) decreases as a protostar evolves. Compared with the deuterium ratio of the molecular ion {{{N}}}₂{{{H}}}⁺, R _D(HNC) seems to decrease slowly with the protostellar evolution.

Keywords: ISM: abundances; ISM: molecules; stars: formation; stars: low-mass

Domains: Sciences of the Universe [physics]

Muneaki Imai, Nami Sakai, Ana López-Sepulcre, Aya E. Higuchi, Yichen Zhang, et al.. Deuterium Fractionation Survey Toward Protostellar Sources in the Perseus Molecular Cloud: HNC Case. The Astrophysical Journal, 2018, 869, ⟨10.3847/1538-4357/aaeb21⟩. ⟨insu-03693519⟩