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Title: Photostability of gas- and solid-phase biomolecules within dense molecular clouds due to soft X-rays
Other Titles: Monthly Notices of the Royal Astronomical Society
Authors: Cavasso Filho, Reinaldo Luiz
Oliveira, Sergio Pilling Guapyassu de
Andrade, Diana Paula de Pinho
Nascimento, E. M.
Marinho, Ricardo dos Reis Teixeira
Boechat-Roberty, Heloisa Maria
Coutinho, Lúcia Helena
Souza, Gerardo Gerson Bezerra de
Castilho, Roberto Barbosa de
Lago, Alexsandre Figueiredo
Brito, Arnaldo Naves de
Keywords: astrobiology;astrochemistry;molecular data;methods: laboratory;ISM: molecules;X-rays: ISM
Issue Date: 2011
Abstract: An experimental photochemistry study involving gas- and solid-phase amino acids (glycine, DL-valine, DL-proline) and nucleobases (adenine and uracil) under soft X-rayswas performed. The aim was to test the molecular stabilities of essential biomolecules against ionizing photon fields inside dense molecular clouds and protostellar discs analogs. In these environments, the main energy sources are the cosmic rays and soft X-rays. The measurements were taken at the Brazilian Synchrotron Light Laboratory (LNLS), employing 150-eV photons. In situ sample analysis was performed by time-of-flight mass spectrometer (TOF-MS) and Fourier transform infrared (FTIR) spectrometer, for gas- and solid-phase analysis, respectively. The half-life of solid-phase amino acids, assumed to be present at grain mantles, is at least 3 × 105 and 3 × 108 yr inside dense molecular clouds and protoplanetary discs, respectively. We estimate that for gas-phase compounds these values increase 1 order of magnitude since the dissociation cross-section of glycine is lower in gas phase than in solid phase for the same photon energy. The half-life of solid-phase nucleobases is about 2–3 orders of magnitude longer than found for amino acids. The results indicate that nucleobases are much more resistant to ionizing radiation than amino acids. We consider these implications for the survival and transfer of biomolecules in space environments.
Description: texto completo: acesso restrito. p.2214–2222.
URI: http://www.repositorio.ufba.br/ri/handle/ri/5511
ISSN: 1365-2966
Appears in Collections:Artigos Publicados em Periódicos (ICADS)

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