Laboratory studies of radiation effects in water ice in the outer solar system

Our groups in Brazil, France and Italy have been active, among others in the world, in performing experiments on physical-chemical effects induced by fast ions colliding with solids (frozen gases, carbonaceous and organic materials, silicates, etc.) of astrophysical interest. The used ions span a very large range of energies, from a few keV to hundreds MeV. Here we present a summary of the results obtained so far on the formation of oxidants (hydrogen peroxide and ozone) after ion irradiation of frozen water, carbon dioxide and their mixtures. Irradiation of pure water ice produces hydrogen peroxide whatever is the used ion and at different temperatures. Irradiation of carbon dioxide and water frozen mixtures result in the production of molecules among which hydrogen peroxide and ozone. The experimental results are discussed in the light of the relevance they have to support the presence of an energy source for biosphere on Europa and other icy moons in the outer Solar System.

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Laboratory Studies of Icy Regoliths in Relation to Observations of Minor Bodies in the Outer Solar System

Earth Moon and Planets ◽

10.1023/b:moon.0000031950.55482.8e ◽

2003 ◽

Vol 92 (1-4) ◽

pp. 337-343 ◽

Cited By ~ 1

Author(s):

A.Chantal Levasseur-Regourd

Keyword(s):

Solar System ◽

Outer Solar System ◽

Laboratory Studies

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Neptune’s Triton: A Moon Rich in Dry Ice and Carbon?

Publications of the Astronomical Society of Australia ◽

10.1017/s1323358000023742 ◽

1990 ◽

Vol 8 (04) ◽

pp. 364-367 ◽

Cited By ~ 1

Author(s):

A. J. R. Prentice

Keyword(s):

Chemical Composition ◽

Solar System ◽

Catalytic Synthesis ◽

Outer Solar System ◽

Solid Carbon ◽

Convective Turbulence ◽

Water Ice ◽

Large Satellite ◽

Unique Composition ◽

Crucial Test

AbstractThe encounter of the spacecraftVoyager 2with Neptune and its large satellite Triton in August 1989 will provide a crucial test of ideas regarding the origin and chemical composition of the outer solar system. In this pre-encounter paper we quantify the possibility that Triton is a captured moon which, like Pluto and Charon, originally condensed as a major planetesimal within the gas ring that was shed by the contracting protosolar cloud at Neptune’s orbit. Ideas of supersonic convective turbulence are used to compute the gas pressure, temperature and rate of catalytic synthesis of CH4, CO2and solid carbon within the protosolar cloud, assuming that all C is initially present as CO. The calculations lead to a unique composition for Triton, Pluto, and Charon: each body consists of, by mass, 18.5% solid CO2ice, 4% graphite, 0.5% CH4ice, 29% methanated water ice and 48% anhydrous rock. This mix has a density consistent with that of the Pluto-Charon system and yields a predicted mean density for Triton of 2.20±0.05 g cm−3, for satellite radius equal to 1750 km.

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Structural and Thermal Icy Satellite Models: Preliminary Results

Publications of the Astronomical Society of Australia ◽

10.1017/s1323358000017392 ◽

1984 ◽

Vol 5 (4) ◽

pp. 487-489

Author(s):

P. J. Thomas

Keyword(s):

Melting Point ◽

Solar System ◽

Methane Hydrates ◽

Outer Solar System ◽

Water Ice ◽

Preliminary Results

The satellites of the outer solar system appear to be composed principally of water ice and silicates, with the presence of ammonia and methane hydrates (Lewis 1971). Although these bodies are small (with radii typically < 1000 km) they can exhibit very active evolutionary histories, due to the low melting point of water ice.

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