Untitled

Hudson, Robert

doi:10.1023/a:1005528702057

Cited by 7 publications

(21 citation statements)

References 8 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The data have been extracted from ISO database 2 . Curve (a) shows the IR spectrum of H 2 O:NH 3 :CO 2 http://iso.esac.esa.int/ida (1:0.2:0.2) ice at 15 K processed 10 minutes of UV photons from hydrogen-discharge lamp (Hudson & Moore 2000). Curve (b) presents the IR spectrum of H 2 O:NH 3 :CO (1:0.2:0.2) ice at 15 K irradiated by 0.8 MeV protons at a dose of 19 eV molec −1 (Hudson & Moore 2000).…”

Section: Cyanate Ion Ocn −mentioning

confidence: 99%

“…Curve (a) shows the IR spectrum of H 2 O:NH 3 :CO 2 http://iso.esac.esa.int/ida (1:0.2:0.2) ice at 15 K processed 10 minutes of UV photons from hydrogen-discharge lamp (Hudson & Moore 2000). Curve (b) presents the IR spectrum of H 2 O:NH 3 :CO (1:0.2:0.2) ice at 15 K irradiated by 0.8 MeV protons at a dose of 19 eV molec −1 (Hudson & Moore 2000). The lowest curve (c) shows the infrared spectrum of H 2 O:NH 3 :CO (1:0.6:0.4) ice at 13 K observed after the bombardment by 46 MeV Ni ions at fluences around 2×10 13 ions cm −2 (this work).…”

Section: Cyanate Ion Ocn −mentioning

confidence: 99%

“…One of the most reactive and important molecules observed from photolysis and radiolysis experiments of ammoniacontaining ices, in which there is a carbon source, is the cyanate ion, OCN − (e.g. Demyk et al 1998;Hudson & Moore 2000;van Broekhuizen et al 2005 and references therein). Its infrared band around 2165 cm −1 was observed in several protostellar sources (e.g.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Radiolysis of ammonia-containing ices by energetic, heavy, and highly charged ions inside dense astrophysical environments

Pilling

Duarte

Silveira³

et al. 2010

A&A

129

View full text Add to dashboard Cite

Deep inside dense molecular clouds and protostellar disks, interstellar ices are protected from stellar energetic UV photons. However, X-rays and energetic cosmic rays can penetrate inside these regions triggering chemical reactions, molecular dissociation, and evaporation processes. We present experimental studies of the interaction of heavy, highly charged, and energetic ions (46 MeV 58 Ni 13+ ) with ammonia-containing ices H 2 O:NH 3 (1:0.5) and H 2 O:NH 3 :CO (1:0.6:0.4) in an attempt to simulate the physical chemistry induced by heavy-ion cosmic rays inside dense astrophysical environments. The measurements were performed inside a high vacuum chamber coupled to the IRRSUD (IR radiation SUD) beamline at the heavy-ion accelerator GANIL (Grand Accelerateur National d'Ions Lourds) in Caen, France. The gas samples were deposited onto a polished CsI substrate previously cooled to 13 K. In-situ analysis was performed by a Fourier transform infrared spectrometer (FTIR) at different fluences. The average values of the dissociation cross-section of water, ammonia, and carbon monoxide due to heavy-ion cosmic ray analogs are ∼2 × 10 −13 , 1.4 × 10 −13 , and 1.9 × 10 −13 cm 2 , respectively. In the presence of a typical heavy cosmic ray field, the estimated half life of the studied species is 2-3 × 10 6 years. The ice compaction (micropore collapse) produced by heavy cosmic rays seems to be at least 3 orders of magnitude higher than that produced by (0.8 MeV) protons. The infrared spectra of the irradiated ice samples exhibit lines of several new species including HNCO, N 2 O, OCN − , and NH + 4 . In the case of the irradiated H 2 O:NH 3 :CO ice, the infrared spectrum at room temperature contains five bands that are tentatively assigned to vibration modes of the zwitterionic glycine (NH + 3 CH 2 COO − ).

show abstract

Section: Cyanate Ion Ocn −mentioning

confidence: 99%

Section: Cyanate Ion Ocn −mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Radiolysis of ammonia-containing ices by energetic, heavy, and highly charged ions inside dense astrophysical environments

Pilling

Duarte

Silveira³

et al. 2010

A&A

129

View full text Add to dashboard Cite

show abstract

“…The fact that the presence of interstellar CO 2 , totally absent and unexpected in the models of gas phase chemistry, because its main formation mechanism is endothermic, was indeed predicted from laboratory experiments, has been largely ignored until its "rediscovery" in 1996 by the ISO-SWS instrument onboard ISO [13]. Other solid phase molecules can also be attributed to energetic processing, where UV photons have usually been more employed than cosmic rays, although it should be stressed that the effects of cosmic rays are remarkably similar, as far as the build-up of more complex molecules is considered (see for example [14]). Actually, as already mentioned, observation of such processes is difficult because of intrinsic properties of water ice making it difficult to observe small abundances species but also because, in a molecular cloud, cold ices in the same line of sight, do mask very efficiently warmer regions where ice sublimates and where, as a result of slow warming up of the grains, for example in hot molecular cores [15], it is nearly impossible to observe the organic material that may remain, as in the laboratory experiments, at the surface on the grains, where all the organic complexity may be found.…”

Section: Astronomical Evidence For Energetic and Thermal Processing Omentioning

confidence: 99%

MICMOC/MICMOS: Photochemistry of van der Waals solids and the rise of the organic molecular complexity

d’Hendecourt

Marcellus

Modica

2014

BIO Web of Conferences

View full text Add to dashboard Cite

Abstract. Ices of well-known composition are widely observed in molecular clouds out of which stars, planets and debris (asteroids, comets) will form. These ices are naturally subjected to energy input in the form of UV photons and charged cosmic particles which are able to start a very rich radical chemistry in the solid state. These phenomena are simulated in the MICMOC experiment which focuses on the possible prebiotic significance of the organic residues that are formed at room temperature. Further than MICMOC, we propose a general prospective of the evolution of this experiment toward the concept of non-directed experiments that may allow simulating the very first steps from the inanimate molecular world to selective pathways toward self-replicating autocatalytic and heterotrophic molecules that could be considered, for a physicist a template for "minimal" life.

show abstract

Section: Astronomical Evidence For Energetic and Thermal Processing Omentioning

confidence: 99%

Molecular complexity in astrophysical environments: From astrochemistry to “astrobiology”?

d’Hendecourt

2011

EPJ Web of Conferences

View full text Add to dashboard Cite

A prebiotic molecule does not exist per-se, but only in a precise environmental contextAbstract. I present in this paper my own view about the intricate problem between the evolution of molecular complexity as observed from an astrophysicist point of view and its possible relation to the problem of the origin of life as we know it on Earth. Using arguments from observational astrophysics, I propose that life cannot really be based on other elements that the ones organizing our own so that other life forms based on totally different elemental and molecular processes are highly improbable. As a consequence terrestrial-type environments are probably the most favorable ones to life's "emergence" and subsequent evolution. Discussing molecular (organic) complexity, I show where this molecular complexity is located in astrophysical environments, mostly within inter/circumstellar solid state materials known as "grains" which, at least partly, end up in comets and asteroids and finally on planetary surfaces as meteorites. Considerations based on non directed laboratory simulations experiments, recent results regarding chiral asymmetry in potentially prebiotic matter and the possible explanation to the determinism about the choice of the L sign of the enantiomeric excesses in meteoritic amino acids, following a plausible astrophysical scenario, lead to the idea that the origin of life on Earth was indeed the result of a rather deterministic phenomenon, albeit difficult if not impossible to apprehend in its intimate mechanisms via a complete understanding of all the processes involved. Finally, the crucial point in supporting the idea of life's ubiquity and wide distribution in our Galaxy (or universe?) lies in the fact that planetary evolution, another astrophysical argument, is a major and very strong constraint for the development of life above its "minimal definition". Life, particularly the complex and evolved one, could be indeed very rare in our Galaxy, although the very large number of exoplanets may be a counter-argument to this statement. However, the deterministic nature of the processes at the origin of life on Earth, the only example we know, together with the progressively increased knowledge of the early conditions on telluric (exo)-planets and in particular those on our primitive Earth, where life did indeed appear, may render possible, in a near future, a semi-quantitative estimate of its occurrence in our Galaxy as well as major improvements in the field of prebiotic chemistry, possibly linked to the one of astrochemistry.

show abstract

Untitled

Cited by 7 publications

References 8 publications

Radiolysis of ammonia-containing ices by energetic, heavy, and highly charged ions inside dense astrophysical environments

Radiolysis of ammonia-containing ices by energetic, heavy, and highly charged ions inside dense astrophysical environments

MICMOC/MICMOS: Photochemistry of van der Waals solids and the rise of the organic molecular complexity

Molecular complexity in astrophysical environments: From astrochemistry to “astrobiology”?

Contact Info

Product

Resources

About