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Solar system exposure to supernova γ radiation
International Journal of Astrobiology ( IF 1.7 ) Pub Date : 2020-11-04 , DOI: 10.1017/s1473550420000348
G. Robert Brakenridge

Planetary habitability may be affected by exposure to γ radiation from supernovae (SNe). Records of Earth history during the late Quaternary Period (40 000 years to present) allow testing for specific SN γ radiation effects. SNe include Type Ia white dwarf explosions, Type Ib, c and II core collapses, and many γ burst objects. Surveys of galactic SNe remnants offer a nearly complete accounting for this time and including SN distances and ages. Terrestrial changes in records of the cosmogenic isotope 14C are here compared to SN-predicted changes. SN γ emission occurs mainly within 3 years; average per-event total emissions of 4 × 1049 erg are used for comparison of close events There are 18 SNe ≤ 1.5 kpc, and brief 14C anomalies are reported for eight of the closest. Four are notable (BP is year before 1950 CE): the older Vela SNR and an abrupt 30‰ del 14C rise at 12 740 BP; S165 and a 20‰ rise at 7431 BP; Vela Jr. and a 14‰ rise at 2765 BP; and HB9 and a 9‰ rise at 5372 BP. Rapid-increase anomalies in 14C production have been attributed to cosmic rays from exceptionally large solar flares. However, the proximity and ages of these SNe, the probable size and duration of their γ emissions, the predicted effects on 14C, and the agreement with 14C records together support SNe causation. Also, the supposed solar-caused 14C anomalies at CE 774 and 993 may instead have been caused by the SNe associated with the G190.9-2.2 and G347.3-00.5 remnants. Both are of appropriate age and distance.

中文翻译:

太阳系暴露于超新星 γ 辐射

行星可居住性可能会受到超新星 (SNe) γ 辐射的影响。第四纪晚期(至今 4 万年)的地球历史记录允许测试特定的 SN γ 辐射效应。SNe 包括 Ia 型白矮星爆炸、Ib 型、c 型和 II 型核心坍塌,以及许多 γ 爆发天体。对银河超新星遗迹的调查提供了对这一时间的近乎完整的解释,包括超新星的距离和年龄。宇宙同位素记录中的陆地变化14此处将 C 与 SN 预测的变化进行比较。SN γ 发射主要发生在 3 年内;每个事件的平均总排放量为 4 × 1049erg 用于比较关闭事件 有 18 个 SNe ≤ 1.5 kpc,简要14最接近的 8 个报告了 C 异常。有四个值得注意(BP 是公元 1950 年之前的一年):较旧的 Vela SNR 和突然的 30‰ del14C 在 12 740 BP 上升;S165 和 20‰ 上涨至 7431 BP;Vela Jr. 和 2765 BP 时上升 14‰;和 HB9 和 9‰ 上涨至 5372 BP。异常迅速增加14C 的产生归因于来自异常大的太阳耀斑的宇宙射线。然而,这些超新星的距离和年龄、它们 γ 发射的可能大小和持续时间、对14C、与协议14C 记录一起支持 SNe 因果关系。此外,所谓的太阳引起的14CE 774 和 993 处的 C 异常可能是由与G190.9-2.2G347.3-00.5残余物。两者都具有适当的年龄和距离。
更新日期:2020-11-04
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