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Title: ELECTRON IRRADIATION AND THERMAL PROCESSING OF MIXED-ICES OF POTENTIAL RELEVANCE TO JUPITER TROJAN ASTEROIDS

In this work we explore the chemistry that occurs during the irradiation of ice mixtures on planetary surfaces, with the goal of linking the presence of specific chemical compounds to their formation locations in the solar system and subsequent processing by later migration inward. We focus on the outer solar system and the chemical differences for ice mixtures inside and outside the stability line for H{sub 2}S. We perform a set of experiments to explore the hypothesis advanced by Wong and Brown that links the color bimodality in Jupiter's Trojans to the presence of H{sub 2}S in the surface of their precursors. Non-thermal (10 keV electron irradiation) and thermally driven chemistry of CH{sub 3}OH–NH{sub 3}–H{sub 2}O (“without H{sub 2}S”) and H{sub 2}S–CH{sub 3}OH–NH{sub 3}–H{sub 2}O (“with H{sub 2}S”) ices were examined. Mid-IR analyses of ice and mass spectrometry monitoring of the volatiles released during heating show a rich chemistry in both of the ice mixtures. The “with H{sub 2}S” mixture experiment shows a rapid consumption of H{sub 2}S molecules and production of OCS molecules after a few hours of irradiation. The heating of the irradiated “with H{sub 2}S” mixture to temperatures above 120 K leads to the appearance of newmore » infrared bands that we provisionally assign to SO{sub 2}and CS. We show that radiolysis products are stable under the temperature and irradiation conditions of Jupiter Trojan asteroids. This makes them suitable target molecules for potential future missions as well as telescope observations with a high signal-to-noise ratio. We also suggest the consideration of sulfur chemistry in the theoretical modeling aimed at understanding the chemical composition of Trojans and KOBs.« less
Authors:
; ; ; ; ; ; ;  [1] ; ;  [2]
  1. Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 (United States)
  2. California Institute of Technology, Division of Geological and Planetary Sciences, Pasadena, CA 91125 (United States)
Publication Date:
OSTI Identifier:
22518537
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 820; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; 79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; AMMONIA; ASTEROIDS; CHEMICAL COMPOSITION; CHEMISTRY; ELECTRONS; HYDROGEN SULFIDES; ICE; IRRADIATION; JUPITER PLANET; KEV RANGE; MASS SPECTROSCOPY; METHANOL; MIXTURES; MOLECULES; SIGNAL-TO-NOISE RATIO; SOLAR SYSTEM; TELESCOPES; WATER