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(Referência obtida automaticamente do Web of Science, por meio da informação sobre o financiamento pela FAPESP e o número do processo correspondente, incluída na publicação pelos autores.)

Photochemistry and desorption induced by X-rays in water rich astrophysical ice analogs: implications for the moon Enceladus and other frozen space environments

Texto completo
Autor(es):
Pilling, S. [1, 2] ; Rocha, W. R. M. [3] ; Freitas, F. M. [1] ; da Silva, P. A. [1, 4]
Número total de Autores: 4
Afiliação do(s) autor(es):
[1] Univ Vale Paraiba UNIVAP, Lab Astroquim & Astrobiol LASA, Av Shishima Hifumi 2911, Sao Jose Dos Campos, SP - Brazil
[2] DCTA, ITA, Dept Fis, BR-12228900 Sao Jose Dos Campos, SP - Brazil
[3] Univ Copenhagen, Niels Bohr Inst Ctr Star & Planet Format, Oster Voldgade 5-7, DK-1350 Copenhagen K - Denmark
[4] Univ Sao Paulo EEL, Escola Engn Lorena, Estr Municipal Campinho S-N, BR-12602810 Lorena, SP - Brazil
Número total de Afiliações: 4
Tipo de documento: Artigo Científico
Fonte: RSC ADVANCES; v. 9, n. 49, p. 28823-28840, SEP 12 2019.
Citações Web of Science: 0
Resumo

Soft X-rays are an important agent for chemical processing in the Solar System and in the interstellar medium. The photolysis and photodesorption processes of H2O-rich ices triggered by soft X-rays was, experimentally, addressed in this paper. The experiments were performed at the Brazilian synchrotron facility LNLS/CNPEN employing broadband radiation (from 6 to 2000 eV; mainly soft X-rays and a small fraction of VUV) in solid samples at temperatures of 20 and 80 K. The icy samples were monitored by infrared spectroscopy. We determined the effective destruction cross section (in the order 10(-18) cm(2)) as well as the formation cross section for the new species produced after the irradiation. Among them, we list OCN-, CO, CO3, CH3OH, H2O2, HCOO-, NH4+, HCONH2 and CH3HCO, mostly formed in the experiment at 80 K. The chemical equilibrium stage was characterized and molecular abundances were quantified. In addition, we discuss a methodology to estimate the amount of unknown species in the ice produced by photolysis. The samples reach chemical equilibrium at fluences around 2-3 x 10(18) cm(-2). Timescales for reaching chemical equilibrium in space environments illuminated by X-rays were given, as well as the desorption yields induced by X-rays. The astrophysical implication on the surface chemistry and desorption processes at the moon Enceladus are provided. (AU)

Processo FAPESP: 15/10492-3 - Estudo da evolução química de gelos astrofísicos na vizinhança de objetos estelares jovens empregando dados experimentais no infravermelho e modelagem computacional
Beneficiário:Will Robson Monteiro Rocha
Linha de fomento: Bolsas no Brasil - Pós-Doutorado
Processo FAPESP: 09/18304-0 - Síntese e degradação de espécies moleculares pré-bióticas em atmosferas planetárias, cometas e gelos interestelares simulados
Beneficiário:Sergio Pilling Guapyassu de Oliveira
Linha de fomento: Auxílio à Pesquisa - Apoio a Jovens Pesquisadores
Processo FAPESP: 13/07657-5 - Modelagem computacional do ambiente circum-estelar de protoestrelas empregando dados de gelos bombardeados por raios cósmicos simulados em laboratório
Beneficiário:Will Robson Monteiro Rocha
Linha de fomento: Bolsas no Brasil - Doutorado