RADIOLYSIS OF NITROGEN AND WATER-ICE MIXTURE BY FAST IONS: IMPLICATIONS FOR KUIPER BELT OBJECTS

Journal Article · Thu Sep 10 04:00:00 EDT 2015 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/810/2/156· OSTI ID:22525436

Silveira, E. F da ^[1]; Bergantini, A. ^[2]; Rothard, H.; Boduch, P. ^[3]

---

1. Departamento de Física, Pontifícia Universidade Católica do Rio de Janeiro, Rua Marquês de São Vicente 225, 22453-900, Rio de Janeiro, RJ (Brazil)
2. Universidade do Vale do Paraiba, Av. Shishima Hifumi, 2911 Urbanova, São José do Campos, SP (Brazil)
3. Centre de Recherche sur les Ions, les Matériaux et la Photonique CIMAP-GANIL (CEA-CNRS-ENSICAEN-UCBN), BP 5133, Boulevard Henri Becquerel, F-14070 Caen Cedex 05 (France)

The participation of condensed nitrogen in the surface chemistry of some objects in the outer solar system, such as Pluto and Triton, is very important. The remote observation of this species using absorption spectroscopy is a difficult task because N{sub 2} is not IR active in the gas phase. Water is also among the most abundant molecules in the surface of these objects; chemical reactions between N{sub 2} and H{sub 2}O induced by cosmic rays are therefore expected. Although pure N{sub 2} ice is hardly identified by IR spectroscopy, the species produced through the processing of the surface ice by cosmic rays may give relevant clues indicating how abundant the N{sub 2} is in the outside layers of the surface of trans-Neptunian objects (TNOs). The objective of this work is to investigate the formation of nitrogenated species induced by cosmic-ray analogs in an ice mixture containing nitrogen and water. Experiments were performed in the GANIL Laboratory by bombarding N{sub 2}:H{sub 2}O (10:1) ice at 15 K with 40 MeV {sup 58}Ni{sup 11+} ions. Evolution of precursor and daughter species was monitored by Fourier transform infrared spectrometry. The main produced species are the nitrogen oxides NO{sub k} (k = 1–3), N{sub 2}O{sub j} (j = 1–5), N{sub 3}, and O{sub 3}. Among them, the N{sub 2}O and N{sub 3} are the most abundant, representing ∼61% of the total column density of the daughter molecules at 10{sup 13} ions cm{sup −2} fluence; the current results indicate that the yield of daughter species from this mixture is low, and this may be one of the reasons why N{sub i}O{sub j} molecules are not usually observed in TNOs.

• OSTI ID: 22525436
• Journal Information: Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 2 Vol. 810; ISSN ASJOAB; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
79 ASTRONOMY AND ASTROPHYSICS
ABSORPTION SPECTROSCOPY
COSMIC RADIATION
FOURIER TRANSFORMATION
GANIL CYCLOTRON
ICE
INFRARED SPECTRA
IONS
MEV RANGE
MOLECULES
NICKEL 58
NITROGEN
NITROUS OXIDE
PLUTO PLANET
RADIOLYSIS
SATELLITES
SOLAR SYSTEM
SOLAR SYSTEM EVOLUTION
WATER