Herschel observations of EXtra-Ordinary Sources (HEXOS): Detection of hydrogen fluoride in absorption towards Orion KL

作者：Phillips T G^*; Bergin E A; Lis D C; Neufeld D A; Bell T A; Wang S; Crockett N R; Emprechtinger M; Blake G A; Caux E; Ceccarelli C; Cernicharo J; Comito C; Daniel F; Dubernet M L; Encrenaz P; Gerin M; Giesen T F; Goicoechea J R; Goldsmith P F; Herbst E; Joblin C; Johnstone D; Langer W D; Latter W D; Lord S D; Maret S; Martin P G; Melnick G J; Menten K M; Morris P; Mueller H S P; Murphy J A; Ossenkopf V

来源：Astronomy & Astrophysics, 2010, 518: L109.

DOI：10.1051/0004-6361/201014570

• ISM: abundances
• ISM: molecules
• submillimeter: ISM

We report a detection of the fundamental rotational transition of hydrogen fluoride in absorption towards Orion KL using Herschel/HIFI. After the removal of contaminating features associated with common molecules ("weeds"), the HF spectrum shows a P-Cygni profile, with weak redshifted emission and strong blue-shifted absorption, associated with the low-velocity molecular outflow. We derive an estimate of 2.9 x 10(13) cm(-2) for the HF column density responsible for the broad absorption component. Using our best estimate of the H(2) column density within the low-velocity molecular outflow, we obtain a lower limit of similar to 1.6 x 10(-10) for the HF abundance relative to hydrogen nuclei, corresponding to similar to 0.6% of the solar abundance of fluorine. This value is close to that inferred from previous ISO observations of HF J = 2-1 absorption towards Sgr B2, but is in sharp contrast to the lower limit of 6 x 10(-9) derived by Neufeld et al. for cold, foreground clouds on the line of sight towards G10.6-0.4.

• 出版日期2010-8