Radiation chemistry of H2O + O2 ices

Cooper, Paul D.; Moore, M. H.; Hudson, R. L.

doi:10.1016/j.icarus.2007.10.002

Cited by 32 publications

(41 citation statements)

References 41 publications

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“…However, at present, there is no experimental evidence of the formation of appreciable quantity of ozone after ion bombardment of pure water ice. The present results confirm that ozone is produced only after addition in the ice of other O-bearing species such as O 2 (Cooper et al 2008; this paper), and CO 2 (Boduch et al 2011, and references therein). Because of the temperatures of the surfaces of the moons (50-100 K), we believe that CO 2 is a better candidate as parent molecule of the observed ozone.…”

Section: Ices In Solar System Objectssupporting

confidence: 87%

Chemistry induced by energetic ions in water ice mixed with molecular nitrogen and oxygen

Boduch

Domaracka

Fulvio

et al. 2012

A&A

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Context. Several molecular species have been observed as frozen gases in cold environments such as grains in the interstellar/circumstellar medium or icy objects in the outer solar system. Because N 2 and O 2 are homonuclear, symmetric molecules are not easily observed. It is therefore relevant to find indirect methods to prove their presence from astronomical observations. Aims. Here we investigate one of the possible indirect methods, namely the formation of specific molecules by cosmic ion bombardment of ices in astrophysical environments that contain O 2 and N 2 . The observation of these molecules in astronomical environments could act as a trojan horse to detect the presence of frozen molecular oxygen and/or nitrogen. Methods. We have conducted ion bombardment experiments of frozen O 2 , H 2 O and their mixtures with N 2 at the laboratories of CIMAP-GANIL at Caen (France) and LASp at Catania (Italy). Different ions ( 13 C 2+ , Ar 2+ and H + ) and energies (30-200 keV) have been used. Results. We have found that 13 CO 2 is formed when carbon ions are implanted in ices containing H 2 O and/or O 2 . Ozone and nitrogen oxides (NO, N 2 O, NO 2 ) are formed in the studied ices containing O 2 and N 2 with different relative abundances. Conclusions. We suggest that ozone and nitrogen oxides are present and have to be searched for in some specific environments such as dense clouds in the interstellar medium and the surfaces of Pluto, Charon and Triton. Their observation could demonstrate the presence of molecular oxygen and/or nitrogen. A possible interest for the observations of atmospheres in exo-planetary objects is also discussed.

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Section: Ices In Solar System Objectssupporting

confidence: 87%

Chemistry induced by energetic ions in water ice mixed with molecular nitrogen and oxygen

Boduch

Domaracka

Fulvio

et al. 2012

A&A

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“…These OH radicals are strongly hydrogen-bonded to water molecules (Cooper et al 2003), and it is not until above 80 K that they can diffuse within a water-ice lattice (Johnson & Quickenden 1997). As pointed out by Cooper et al (2008), energetic OH radicals can diffuse short distances along ion tracks and react at 10 K, but bulk diffusion probably does not occur.…”

Section: Hydrogen Peroxidementioning

confidence: 99%

Radiolysis of H₂O:CO₂ices by heavy energetic cosmic ray analogs

Pilling

Duarte²,

Domaracka

et al. 2010

A&A

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An experimental study of the interaction of heavy, highly charged, and energetic ions (52 MeV 58 Ni 13+ ) with pure H 2 O, pure CO 2 and mixed H 2 O:CO 2 astrophysical ice analogs is presented. This analysis aims to simulate the chemical and the physicochemical interactions induced by heavy cosmic rays inside dense and cold astrophysical environments, such as molecular clouds or protostellar clouds. The measurements were performed at the heavy ion accelerator GANIL (Grand Accélérateur National d'Ions Lourds in Caen, France). The gas samples were deposited onto a CsI substrate at 13 K. In-situ analysis was performed by a Fourier transform infrared (FTIR) spectrometer at different fluences. Radiolysis yields of the produced species were quantified. The dissociation cross sections of pure H 2 O and CO 2 ices are 1.1 and 1.9 ×10 −13 cm 2 , respectively. For mixed H 2 O:CO 2 (10:1), the dissociation cross sections of both species are about 1 × 10 −13 cm 2 . The measured sputtering yield of pure CO 2 ice is 2.2 × 10 4 molec ion −1 . After a fluence of 2−3 × 10 12 ions cm −2 , the CO 2 /CO ratio becomes roughly constant (∼0.1), independent of the initial CO 2 /H 2 O ratio. A similar behavior is observed for the H 2 O 2 /H 2 O ratio, which stabilizes at 0.01, independent of the initial H 2 O column density or relative abundance.

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“…Gaidos et al (1999) suggested that life in sealed oceans under thick ice cover would rapidly die out due to depletion of redox pairs. Gaidos et al (1999) been proposed that oxidants produced by radiation on the surface of the icy satellites could be carried to subsurface liquid water reservoirs that may contain reductants (Chyba and Phillips, 2001;Johnson et al, 2003;Cooper et al, 2007;Hand et al, 2007;Moore et al, 2007). Parkinson et al (2007Parkinson et al ( , 2008 considered Enceladus and argued for a similar, strong source of surface oxidants there.…”

Section: Possible Ecosystems On Enceladusmentioning

confidence: 99%

The Possible Origin and Persistence of Life on Enceladus and Detection of Biomarkers in the Plume

et al. 2008

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The jets of icy particles and water vapor issuing from the south pole of Enceladus are evidence for activity driven by some geophysical energy source. The vapor has also been shown to contain simple organic compounds, and the south polar terrain is bathed in excess heat coming from below. The source of the ice and vapor, and the mechanisms that accelerate the material into space, remain obscure. However, it is possible that a liquid water environment exists beneath the south polar cap, which may be conducive to life. Several theories for the origin of life on Earth would apply to Enceladus. These are (1) origin in an organic-rich mixture, (2) origin in the redox gradient of a submarine vent, and (3) panspermia. There are three microbial ecosystems on Earth that do not rely on sunlight, oxygen, or organics produced at the surface and, thus, provide analogues for possible ecologies on Enceladus. Two of these ecosystems are found deep in volcanic rock, and the primary productivity is based on the consumption by methanogens of hydrogen produced by rock reactions with water. The third ecosystem is found deep below the surface in South Africa and is based on sulfur-reducing bacteria consuming hydrogen and sulfate, both of which are ultimately produced by radioactive decay. Methane has been detected in the plume of Enceladus and may be biological in origin. An indicator of biological origin may be the ratio of non-methane hydrocarbons to methane, which is very low (0.001) for biological sources but is higher (0.1-0.01) for nonbiological sources. Thus, Cassini's instruments may detect plausible evidence for life by analysis of hydrocarbons in the plume during close encounters.

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Radiation chemistry of H2O + O2 ices

Cited by 32 publications

References 41 publications

Chemistry induced by energetic ions in water ice mixed with molecular nitrogen and oxygen

Chemistry induced by energetic ions in water ice mixed with molecular nitrogen and oxygen

Radiolysis of H₂O:CO₂ices by heavy energetic cosmic ray analogs

The Possible Origin and Persistence of Life on Enceladus and Detection of Biomarkers in the Plume

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Radiation chemistry of H2O + O2 ices

Cited by 32 publications

References 41 publications

Chemistry induced by energetic ions in water ice mixed with molecular nitrogen and oxygen

Chemistry induced by energetic ions in water ice mixed with molecular nitrogen and oxygen

Radiolysis of H2O:CO2ices by heavy energetic cosmic ray analogs

The Possible Origin and Persistence of Life on Enceladus and Detection of Biomarkers in the Plume

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Product

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Radiolysis of H₂O:CO₂ices by heavy energetic cosmic ray analogs