论文标题
估计具有稀土气氛的陆地行星和卫星上微生物代谢的电离辐射诱导的辐射分解的潜力
Estimating the potential of ionizing radiation-induced radiolysis for microbial metabolism on terrestrial planets and satellites with rarefied atmospheres
论文作者
论文摘要
已知电离辐射对生物学具有破坏性作用,从而损害了活性氧(ROS)的DNA,细胞和产生。虽然直接暴露于高辐射剂量确实不利于生物学活性,但电离辐射可以可以,在某些情况下可以产生许多生物学上有用的产品。一种这样的机制是通过带电的粒子诱导的辐射溶解生产生物学上有用的产物。某些副产品不可能使用低能辐射(例如阳光)产生,从而为使用它们开辟了新的生命途径。手稿的主要目的是探索放射性宜居区(RHZ)的概念,在该区域中,GCR诱导的放射解溶解的化学可能可用于代谢活性。我们首先使用GEANT4数值模型来计算能量沉积和电子生产率,然后估算当前的生产和可能的化学途径,这对于支持MARS,Europa和Ecceladus的生物活性很有用。 RHZ的概念为理解高辐射环境中的生命潜力提供了一个新颖的框架。通过将能量沉积计算与微生物细胞的能量需求相结合,我们定义了火星,欧罗巴和埃塞拉多斯的RHZ。这些区域代表了放射分解驱动的能源产生足以维持微生物代谢的区域。我们发现细菌细胞密度最高,其次是火星和欧罗巴。我们讨论了这些机制对这种物体在太阳系及其他地区的宜居性的含义。
Ionizing radiation is known to have a destructive effect on biology by causing damage to the DNA, cells, and production of Reactive Oxygen Species (ROS), among other things. While direct exposure to high radiation dose is indeed not favorable for biological activity, ionizing radiation can, and in some cases is known to produce a number of biologically useful products. One such mechanism is the production of biologically useful products via charged particle-induced radiolysis. Some of the byproducts are impossible to produce with lower-energy radiation (such as sunlight), opening up new avenues for life to utilize them. The main objective of the manuscript is to explore the concept of a Radiolytic Habitable Zone (RHZ), where the chemistry of GCR-induced radiolysis can be potentially utilized for metabolic activity. We first calculate the energy deposition and the electron production rate using the GEANT4 numerical model, then estimate the current production and possible chemical pathways which could be useful for supporting biological activity on Mars, Europa and Enceladus. The concept of RHZ provides a novel framework for understanding the potential for life in high-radiation environments. By combining energy deposition calculations with the energy requirements of microbial cells, we have defined the RHZ for Mars, Europa, and Enceladus. These zones represent the regions where radiolysis-driven energy production is sufficient to sustain microbial metabolism. We find that bacterial cell density is highest in Enceladus, followed by Mars and Europa. We discuss the implications of these mechanisms for the habitability of such objects in the Solar system and beyond.