|The chemistry of nitrogen in dark clouds
|Nitrogen is the fifth most abundant element in the local Universe. It is essential component of molecules associated to Earth-type life. Yet, the reservoir of nitrogen in the dense ISM, where stars, and ultimately planets, form, is not known. This is for good reasons. The main reservoir of gas-phase nitrogen are expected to be N or N2, and it is likely that most of the nitrogen be indeed frozen-out on dust grains in the form of ammonia ices. However, N and N2 are not observable in the shielded environments characterizing the embryos of star-forming regions. Hence, all what is know about nitrogen must rely on indirect observations of N-bearing molecules, the lightest (and thus among the easiest to form) of which are hardly detectable from the ground. To date, and despite longstanding efforts, our comprehension of the chemistry of nitrogen remains elusive. The HSO-HIFI instrument is opening new avenues in this respect, allowing astronomers to readily detect nitrogen hydrides and several key species of the nitrogen chemistry. This is the aim of this proposal. We propose the observation of key species that are observable only with Herschel. Those include NH, NH2 and NH3 (in their ortho and para forms), as well as their deuterated isotopologues, and other pivotal species like CH and CH2. This corpus of observations in order will allow to assess our understanding of the chemistry of nitrogen in dark cloud conditions, and answer the fundamental and open question, whether dust processes are necessary catalysts in this chemistry.
|Chemical tracers of episodic accretion in low-mass protostars . Visser Ruud et al. . Astronomy & Astrophysics, Volume 577, id.A102, 12 pp. . 577 . 10.1051/0004-6361/201425365 . 2015A&A...577A.102V ,
|Herschel was launched on 14 May 2009! It is the fourth 'cornerstone' mission in the ESA science programme. With a 3.5 m Cassegrain telescope it is the largest space telescope ever launched. It is performing photometry and spectroscopy in approximately the 55-671 µm range, bridging the gap between earlier infrared space missions and groundbased facilities.
|Publisher And Registrant
|European Space Agency
|European Space Agency, 2013, OT1_philybla_1, SPG v14.1.0. https://doi.org/10.5270/esa-hvya6k1