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In order to investigate the role of medium mass cosmic rays and energetic solar particles in the processing of N2-rich ice on frozen moons and cold objects in the outer solar system, the bombardment of an N2 : H2O : NH3 : CO2 (98.2 : 1.5 : 0.2 : 0.1) ice mixture at 16 K employing 15.7 MeV 16O5+ was performed. The changes in the ice chemistry were monitored and quantified by Fourier transformed infrared spectroscopy (FTIR). The results indicate the formation of azide radicals (N3), and nitrogen oxides, such as NO, NO2, and N2O, as well as the production of CO, HNCO, and OCN−. The effective formation and destruction cross-sections are roughly on the order of 10−12 cm2 and 10−13 cm2, respectively. From laboratory molecular analyses, we estimated the destruction yields for the parent species and the formation yields for the daughter species. For N2, this value was 9.8 × 105 molecules per impact of ions, and for the most abundant new species (N3), it was 1.1 × 105 molecules per impact of ions. From these yields, an estimation of how many species are destroyed or formed in a given timescale (108 years) in icy bodies in the outer solar system was calculated. This work reinforces the idea that such physicochemical processes triggered by cosmic rays, solar wind, and magnetospheric particles (medium-mass ions) in nitrogen-rich ices may play an important role in the formation of molecules (including pre-biotic species precursors such as amino acids and other “CHON” molecules) in very cold astrophysical environments, such as those in the outer region of the solar system (e.g. Titan, Triton, Pluto, and other KBOs). [ABSTRACT FROM AUTHOR]

This work presents a physicochemical study of frozen amorphous methane (at 16 K) under bombardment by medium-mass ions (15.7 MeV 16O5+) with implications for icy bodies in the outer Solar System exposed to the action of cosmic rays and energetic particles. The experiment was performed at the Grand Accélérateur National d'Ions Lourds (GANIL) located in Caen, France. The results demonstrate that irradiation of CH4-containing ices by swift medium mass ions with delivered energy covering both stopping power regimes until its implantation on ice (i.e. electronic and nuclear) leads to the production of many hydrocarbons, such as C2H2, C2H4, C2H6, and C3H8 (the most abundant daughter species produced). Values for the effective dissociation cross section of CH4 and the average value for the effective formation cross-sections of its daughter species were about 10−14 cm2 and 10−15 cm2, respectively. The half-life of methane ice in the presence of swift medium mass ions extrapolated to some outer Solar System environments is estimated to be around 106 years. The measured sputtering yield of methane due to incoming swift ions was about 7.30 × 105 molecules per impact. Such parameters can be used as models to estimate the amount of CH4 and other molecular species desorbed from the icy surfaces that are constantly being incorporated to the gaseous atmosphere in the vicinity of these outer Solar System bodies due to the presence of energetic particles and cosmic rays. [ABSTRACT FROM AUTHOR]

We present new experimental results on thermal and ion irradiation processing of frozen ammonia–carbon dioxide mixtures. Some mixtures were deposited at low temperatures (T≈ 16 K). Upon warming up to 160 K, complex chemical reactions occur leading to the formation of new molecules and, in particular, of ammonium carbamate. We also show that the same species are produced when water is the dominant species in the ternary mixture with ammonia and carbon dioxide. The samples have been irradiated with 144 keV S9+ ions at 16 K and 50 K. Also in this case, new chemical species are formed as e.g. ammonium formate, CO and OCN−. The results are discussed in the light of their relevance to the chemical evolution of ices in the interstellar medium and in the solar system. In particular, we suggest searching for them among the gas phase species sublimating from grains around young stellar objects and from the cometary nuclei approaching the Sun. [ABSTRACT FROM AUTHOR]

In order to investigate the role of medium mass cosmic rays and energetic solar particles in the processing of N 2 -rich ice on frozen moons and cold objects in the outer solar system, the bombardment of an N 2  : H 2 O : NH 3  : CO 2 (98.2 : 1.5 : 0.2 : 0.1) ice mixture at 16 K employing 15.7 MeV 16 O 5+ was performed. The changes in the ice chemistry were monitored and quantified by Fourier transformed infrared spectroscopy (FTIR). The results indicate the formation of azide radicals (N 3 ), and nitrogen oxides, such as NO, NO 2 , and N 2 O, as well as the production of CO, HNCO, and OCN - . The effective formation and destruction cross-sections are roughly on the order of 10 -12 cm 2 and 10 -13 cm 2 , respectively. From laboratory molecular analyses, we estimated the destruction yields for the parent species and the formation yields for the daughter species. For N 2 , this value was 9.8 × 10 5 molecules per impact of ions, and for the most abundant new species (N 3 ), it was 1.1 × 10 5 molecules per impact of ions. From these yields, an estimation of how many species are destroyed or formed in a given timescale (10 8 years) in icy bodies in the outer solar system was calculated. This work reinforces the idea that such physicochemical processes triggered by cosmic rays, solar wind, and magnetospheric particles (medium-mass ions) in nitrogen-rich ices may play an important role in the formation of molecules (including pre-biotic species precursors such as amino acids and other "CHON" molecules) in very cold astrophysical environments, such as those in the outer region of the solar system (e.g. Titan, Triton, Pluto, and other KBOs).

This work presents a physicochemical study of frozen amorphous methane (at 16 K) under bombardment by medium-mass ions (15.7 MeV 16 O 5+ ) with implications for icy bodies in the outer Solar System exposed to the action of cosmic rays and energetic particles. The experiment was performed at the Grand Accélérateur National d'Ions Lourds (GANIL) located in Caen, France. The results demonstrate that irradiation of CH 4 -containing ices by swift medium mass ions with delivered energy covering both stopping power regimes until its implantation on ice (i.e. electronic and nuclear) leads to the production of many hydrocarbons, such as C 2 H 2 , C 2 H 4 , C 2 H 6 , and C 3 H 8 (the most abundant daughter species produced). Values for the effective dissociation cross section of CH 4 and the average value for the effective formation cross-sections of its daughter species were about 10 -14 cm 2 and 10 -15 cm 2 , respectively. The half-life of methane ice in the presence of swift medium mass ions extrapolated to some outer Solar System environments is estimated to be around 10 6 years. The measured sputtering yield of methane due to incoming swift ions was about 7.30 × 10 5 molecules per impact. Such parameters can be used as models to estimate the amount of CH 4 and other molecular species desorbed from the icy surfaces that are constantly being incorporated to the gaseous atmosphere in the vicinity of these outer Solar System bodies due to the presence of energetic particles and cosmic rays.

An experimental study of the interaction of highly charged, energetic ions (52 MeV (58)Ni(13+) and 15.7 MeV (16)O(5+)) with mixed H(2)O : C(18)O(2) astrophysical ice analogs at two different temperatures is presented. This analysis aims to simulate the chemical and the physicochemical interactions induced by cosmic rays inside dense, cold astrophysical environments, such as molecular clouds or protostellar clouds as well at the surface of outer solar system bodies. The measurements were performed at the heavy ion accelerator GANIL (Grand Accelerateur National d'Ions Lourds) in Caen, France. The gas samples were deposited onto a CsI substrate at 13 K and 80 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 section at 13 K of both H(2)O and CO(2) is about 3-4 times smaller when O ions are employed. The ice temperature seems to affect differently each species when the same projectile was employed. The formation cross section at 13 K of molecules such as C(18)O, CO (with oxygen from water), and H(2)O(2) increases when Ni ions are employed. The formation of organic compounds seems to be enhanced by the oxygen projectiles and at lower temperatures. In addition, because the organic production at 13 K is at least 4 times higher than the value at 80 K, we also expect that interstellar ices are more organic-rich than the surfaces of outer solar system bodies.