| Full text | |
| Author(s): |
Total Authors: 2
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| Affiliation: | [1] Univ Vale Paraiba UNIVAP, Inst Pesquisa & Desenvolvimento IP&D, Av Shishima Hifumi 2911, BR-12244000 Sao Jose Dos Campos, SP - Brazil
Total Affiliations: 1
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| Document type: | Journal article |
| Source: | Monthly Notices of the Royal Astronomical Society; v. 498, n. 1, p. 689-701, OCT 2020. |
| Web of Science Citations: | 1 |
| Abstract | |
In this study, we employed broad-band X-rays (6-2000 eV) to irradiate the frozen acetone CH3COCH3, at the temperature of 12 K, with different photon fluences up to 2.7 x 10(18) photons cm(-2). Here, we consider acetone as a representative complex organic molecule (COM) present on interstellar ice grains. The experiments were conduced at the Brazilian Synchrotron facility (LNLS/CNPEN) employing infrared spectroscopy (FTIR) to monitor chemical changes induced by radiation in the ice sample. We determined the effective destruction cross-section of the acetone molecule and the effective formation cross-section for daughter species. Chemical equilibrium, obtained for fluence 2 x 10(18) photons cm(-2), and molecular abundances at this stage were determined, which also includes the estimates for the abundance of unknown molecules, produced but not detected, in the ice. Time-scales for ices, at hypothetical snow line distances, to reach chemical equilibrium around several compact and main-sequence X-ray sources are given. We estimate time-scales of 18 d, 3.6 and 1.8 months, 1.4 x 10(9)-6 x 10(11) yr, 600 and 1.2 x 10(7) yr, and 10(7) yr, for the Sun at 5 au, for O/B stars at 5 au, for white dwarfs at 1 LY, for the Crab pulsar at 2.25 LY, for Vela pulsar at 2.25 LY, and for Sagittarius A{*} at 3 LY, respectively. This study improves our current understanding about radiation effects on the chemistry of frozen material, in particular, focusing for the first time, the effects of X-rays produced by compact objects in their eventual surrounding ices. (AU) | |
| FAPESP's process: | 13/07657-5 - Computational modeling of circumstellar environment of protostars by employing data of bombarded ices with cosmic rays simulated in laboratory. |
| Grantee: | Will Robson Monteiro Rocha |
| Support Opportunities: | Scholarships in Brazil - Doctorate |
| FAPESP's process: | 09/18304-0 - Synthesis and degradation of prebiotic molecular species at planetary atmospheres, comets and interstellar ice analogs |
| Grantee: | Sergio Pilling Guapyassu de Oliveira |
| Support Opportunities: | Research Grants - Young Investigators Grants |
| FAPESP's process: | 15/10492-3 - Study about the chemical evolution of astrophysical ices in the vicinity of young stellar objects employing experimental data in the infrared and computational modeling codes |
| Grantee: | Will Robson Monteiro Rocha |
| Support Opportunities: | Scholarships in Brazil - Post-Doctoral |