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强紫外线的系外行星可能不是不可居住的:来自沙漠的证据
Tejinder Singh1, Christos D Georgiou2, Christopher S Jeffrey3
1Desert Research Institute, Las Vegas, Nevada, USA.
Astrobiology
|June 16, 2025
概括
沙漠水对强烈的紫外线C (UVC) 辐射表现出了显著的弹性,这表明围绕M和F恒星运行的系外行星可能仍然支持生命. 这项研究证明了皮层对紫外线的保护作用,挑战了关于可居住性的假设.
科学领域:
- 天体生物学 天体生物学
- 植物科学 植物科学
- 辐射生物学 辐射生物学
背景情况:
- 类似地球的系外行星经常被发现围绕M型和F型恒星运行.
- 这些恒星发射强烈的紫外线C (UVC) 辐射,特别是在爆发期间.
- 在这样的条件下,系外行星的可居住性是一个重要的问题.
研究的目的:
- 为了研究沙漠的紫外线耐受性 *Clavascidium lacinulatum*.
- 评估UVC强度高的系外行星对光合作用生物的潜在可居住性.
- 了解水对高紫外线水平的保护机制.
主要方法:
- 用254nm紫外线 (55W/m2) 持续照射 *Clavascidium lacinulatum* 3个月.
- 将状植物光生物细胞的紫外线抗性与纯培养和Deinococcus radiodurans中的细胞进行比较.
- 分析类皮质的保护性化合物和机制.
主要成果:
- 在UVC暴露3个月后,只有50%的藻光生物细胞失活了.
- 纯培养中的光生物体细胞和Deinococcus radiodurans在相同的条件下在60秒内失活.
- 在皮层中的二代代谢物使其变得UVC不透明,提供了显著的保护.
结论:
- 鱼具有强大的保护机制,可以抵御强烈的紫外线辐射.
- *Clavascidium lacinulatum*的皮质有效地保护其内部细胞免受UVC损伤.
- 光合作用生物有可能居住在具有高紫外线水平的系外行星上,这与之前的假设相反.
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