Related papers: Interstellar triply deuterated ammonia
High deuterium fractionation is observed in various types of environment such as prestellar cores, hot cores and hot corinos. It has proven to be an efficient probe to study the physical and chemical conditions of these environments. The…
Clouds of high infrared extinction are promising sites of massive star/cluster formation. A large number of cloud cores discovered in recent years allows investigation of possible evolutionary sequence among cores in early phases. We have…
We carry out Monte-Carlo simulation to study deuterium enrichment of interstellar grain mantles under various physical conditions. Based on the physical properties, various types of clouds are considered. We find that in diffuse cloud…
We present the results of models of the chemistry, including deuterium, in the inner regions of protostellar disks. We find good agreement with recent gas phase observations of several (non--deuterated) species. We also compare our results…
We present measurements of the column densities of interstellar DI, OI, NI, and H2 made with FUSE, and of HI made with IUE toward the sdO star LSE 44, at a distance of 554+/-66 pc. This target is among the seven most distant Galactic sight…
N-bearing molecules (like N2H+ or NH3) are excellent tracers of high-density, low-temperature regions like dense cloud cores and could shed light into snowlines in protoplanetary disks and the chemical evolution of comets. However,…
With a goal toward deriving the physical conditions in external galaxies, we present a study of the ammonia (NH$_3$) emission and absorption in a sample of star forming systems. Using the unique sensitivities to kinetic temperature afforded…
The detection of NH3 inversion lines up to the (J,K)=(6,6) level is reported toward the central regions of the nearby galaxies NGC253, Maffei2, and IC342. The observed lines are up to 406K (for (J,K)=(6,6)) and 848K (for the (9,9)…
Presented here are NOEMA interferometric observations of the neighboring hot cores W3(H$_{2}$O) and W3(OH). The presence of two star-forming cores at different evolutionary stages within the same parent cloud presents a unique opportunity…
The level of isotopic fractionation in molecules provides insights into their formation environments and how they formed. In this article, we review hydrogen and nitrogen isotopic fractionation in low-mass star-forming regions. Interstellar…
Observations of star forming environments revealed that the abundances of some deuterated interstellar molecules are markedly larger than the cosmic D/H ratio of 10-5. Possible reasons for this pointed to grain surface chemistry. How- ever,…
Deuterated molecules are a useful diagnostic tool to probe the evolution and the kinematics in the earliest stages of star formation. Due to the low temperatures and high densities in the centre of pre-stellar cores, the deuterium fraction…
High-mass stars are expected to form from dense prestellar cores. Their precise formation conditions are widely discussed, including their virial condition, which results in slow collapse for super-virial cores with strong support by…
Infrared-dark high-mass clumps are among the most promising objects to study the initial conditions of the formation process of high-mass stars and rich stellar clusters. In this work, we have observed the (3-2) rotational transition of…
We have observed the J=3-2 transition of N2H+ and N2D+ to investigate the trend of deuterium fractionation with evolutionary stage in three selected regions in the Infrared Dark Cloud (IRDC) G28.34+0.06 with the Submillimeter Telescope…
We investigated the chemistry of nitrogen--containing species, principally isotopomers of CN, HCN, and HNC, in a sample of pre-protostellar cores. We used the IRAM 30 m telescope to measure the emission in rotational and hyperfine…
The interstellar abundances of D I, N I, and O I in the local ISM are studied us ing high-resolution spectra of four hot white dwarfs. The spectra of GD 246, WD 2331$-$475, HZ 21, and Lan 23 were obtained with the {\it Far Ultraviolet…
The physical and chemical properties of cold and dense molecular clouds are key to understanding how stars form. Using the IRAM 30 m and NRO 45 m telescopes, we carried out a Multiwavelength line-Imaging survey of the 70 $\mu$m dark and…
Deuterium fractionation is dependent on various physical and chemical parameters. Thus, the formation location and thermal history of material in the solar system is often studied by measuring its D/H ratio. This requires knowledge about…
The origin of the observed variability of the gas-phase D/H ratio in the local interstellar medium is still debated, and in particular the role of deuterium depletion onto dust grains. Here we extend the study of the relationship between…