Related papers: Isotopic fractionation in interstellar molecules
The differential isospin-fractionation (IsoF) during the liquid-gas phase transition in dilute asymmetric nuclear matter is studied as a function of nucleon momentum. Within a self-consistent thermal model it is shown that the…
Deuterium enrichment of interstellar methanol is reproduced experimentally for the first time via grain-surface H-D substitution in solid methanol at an atomic D/H ratio of 0.1. Although previous gas-grain models successfully reproduce the…
H2S is thought to be the main sulphur reservoir in the ice, being therefore a key molecule to understand sulphur chemistry in the star formation process and to solve the missing sulphur problem. The H2S deuterium fraction can be used to…
Isotopic ratios have been used as chemical diagnostics to investigate the origin of the material in the Solar System. We have determined the HCN, HNC, and N2H+ isotopic ratios and the chemical age in a large sample of 23 starless cores…
The initial stage of star formation is a complex area study because of its high density and low temperature. Under such conditions, many molecules become depleted from the gas phase by freezing out onto dust grains. However, the deuterated…
The recent observation of complex organic molecules (COMs) in interstellar ices by the James Webb Space Telescope (JWST), along with previous gas-phase detections, underscores the importance of grain surface and ice mantle chemistry in the…
Using the Green Bank Telescope (GBT), we have obtained accurate measurements of the $^{14}$N/$^{15}$N isotopic ratio in ammonia in two nearby cold, dense molecular clouds, Barnard~1 and NGC 1333. The $^{14}$N/$^{15}$N ratio in Barnard~1,…
In the interstellar medium carbon exists in the form of two stable isotopes $^{12}$C and $^{13}$C and their ratio is a good indicator of nucleosynthesis in galaxies. However, chemical fractionation can potentially significantly alter this…
Recent observations indicate that organic molecules are prevalent towards starless and prestellar cores. Deuteration of these molecules has not been well-studied during the starless phase. Published observations of singly-deuterated…
Many chemical models of dense interstellar clouds predict that the majority of gas-phase elemental nitrogen should be present as N2, with an abundance approximately five orders of magnitude less than that of hydrogen. As a homonuclear…
During the next decade a tremendous advance will take place in instrumentation for spectroscopy of the interstellar medium. Major new facilities (ALMA, SOFIA, APEX, LMT, Herschel and others) will be constructed and commissioned, so that the…
The nitrogen isotope ratio 14N/15N is a powerful tool to trace Galactic stellar nucleosynthesis and constraining Galactic chemical evolution. Previous observations have found lower 14N/15N ratios in the Galactic center and higher values in…
Nitrogen isotopic ratios are a key tool for tracing Galactic stellar nucleosynthesis. We present the first study of the $^{14}$N/$^{15}$N abundance ratio in the outer regions of the Milky Way (namely, for galactocentric distances, $R_{\rm…
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…
We have probed the fragmentation dynamics in a bent triatomic molecule, water, a non-planar molecule, methanol, and a planar ring-structured molecule, benzene, using 100 fs duration pulses of linearly and circularly polarized, infrared,…
We report on a search for Interstellar CH2D+. Four transitions occur in easily accessible portions of the spectrum; we report on emission at the frequencies of these transitions toward high column density star-forming regions. While the…
We observed the J=9-8 and 10-9 rotational lines of three13C isotopologues of HC3N in L1527 and G28.28-0.36 with the 45-m radio telescope of the Nobeyama Radio Observatory in order to constrain the main formation mechanisms of HC3N in each…
Dense cloud cores present chemical differentiation due to the different distribution of C-bearing and N-bearing molecules, the latter being less affected by freeze-out onto dust grains. In this letter we show that two C-bearing molecules,…
[abridged] The enhanced degrees of deuterium fractionation observed in envelopes around protostars demonstrate the importance of chemistry at low temperatures, relevant in pre- and protostellar cores. formaldehyde is an important species in…
The influence of turbulent mixing on the chemistry of the interstellar medium has so far received little attention. Previous studies of this effect have suggested that it might play an important role in mixing the various phases of the…