CH $_3$ COCH $_3$冰的X射线光分解：致密物体对天体物理学冰的辐射效应的含意
X-ray photolysis of CH$_3$COCH$_3$ ice: Implications for the radiation effects of compact objects towards astrophysical ices
摘要：
在这项研究中，我们采用宽带X射线（$6-2000$ eV）照射冷冻丙酮CH $_3$ COCH $_3$，在12 K的温度下，不同的光子通量高达$2.7\times 10^{18}$光子cm $^{-2}$。在这里，我们认为丙酮作为一个代表性的复杂的有机分子（COM）存在于星际冰粒。实验在巴西同步加速器设施（LNLS/CNPEN）进行，采用红外光谱（FTIR）监测辐射引起的冰样中的化学变化。我们确定了丙酮分子的有效破坏截面和子物种的有效形成截面。化学平衡，获得的注量$2\times 10^{18}$光子cm $^{-2}$，并在此阶段的分子丰度进行了测定，其中还包括未知分子的丰度，产生但未检测到，在冰的估计。给出了在假设雪线距离处，冰在几个紧凑的主序星X射线源周围达到化学平衡的时间尺度。我们估计的时间尺度为18天，3.6和1.8个月，$1.4\times 10^9-6\times 10^{11}$年，600和$1.2\times 10^7$年，$10^7$年，太阳在5 AU，O/B星在5 AU，白矮星在1 LY，蟹状星云脉冲星在2.25 LY，船帆座脉冲星在2.25 LY，人马座A* 在3 LY，分别。这项研究提高了我们目前对辐射对冻结物质化学性质的影响的理解，特别是首次关注了致密物体在其最终周围的冰中产生的X射线的影响。
英文摘要：
In this study, we employed broadband X-rays ($6-2000$ eV) to irradiate the frozen acetone CH$_3$COCH$_3$, at the temperature of 12 K, with different photon fluences up to $2.7\times 10^{18}$ 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 $2\times 10^{18}$ 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. Timescales for ices, at hypothetical snow line distances, to reach chemical equilibrium around several compact and main-sequence X-ray sources are given. We estimate timescales of 18 days, 3.6 and 1.8 months, $1.4\times 10^9-6\times 10^{11}$ years, 600 and $1.2\times 10^7$ years, and $10^7$ years, 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.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
