LExEn: Stochastic Photochemistry and Stochastic Photobiology in the Galactic Environment

LExEn：银河环境中的随机光化学和随机光生物学

• 批准号: 9907582
• 负责人: John Wheeler
• 金额: $ 25万
• 依托单位: University of Texas at Austin
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1999
• 资助国家: 美国
• 起止时间: 1999-09-15 至 2002-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9907582&HistoricalAwards=false
• 关键词: LExEn; Stochastic; Photochemistry; Photobiology; Galactic

ABSTRACTP.I.: Wheeler, J. Craig Proposal Number: AST-9907582"LExEn: Stochastic Photochemistry and Photobiology in the Galactic Environment"This project seeks to understand the importance and implications of a new type of extreme environmental influence that should affect the development of microbial life in most planetary and satellite systems: frequent short-lived jolts of high-energy photons and particles that are an inevitable consequence of the Galactic environment. These events include various phenomena associated with supernovae, novae, gamma ray bursts, and supernova remnant shocks. The project will demonstrate, by comparing the estimated source fluxes with the solar background and minimum levels for biological activity, whether these events can drive non-equilibrium photochemistry in the atmospheres of planets and satellites. They may also be a potent intermittent source of biological alteration for microorganisms on planets with or without ultraviolet shields like ozone. Specific problems that are being addressed include: (1) the probability that these various sources of high energy radiation exceed the background flux received from the Sun; (2) hydrodynamics and radiative transfer in the astronomical sources, especially in the early shock breakout stage of supernovae; (3) transformation of the emitted spectral energy distributions as they propagate through the model prebiotic, Archean, and post-ozone atmospheres; (4) non-equilibrium photochemistry in outer Solar system bodies like Titan; and (5) biological effect of both the calculated surface fluxes and the variation in stellar flux due to changes in atmospheric chemistry on microorganisms.This project is part of the NSF Life in Extreme Environments (LExEn) program.Funding is provided by the NSF Division of Astronomical Sciences StellarAstronomy & Astrophysics (SAA) program and the NSF Division of Molecular& Cellular Biosciences (MCB).

摘要一：惠勒，克雷格 提案编号：AST-9907582“LExEn：银河系环境中的随机光化学和光生物学“该项目旨在了解一种新型极端环境影响的重要性和影响，这种影响应该会影响大多数行星和卫星系统中微生物生命的发展：高能光子和粒子的频繁短暂震动是银河系环境的必然后果。 这些事件包括与超新星、新星、伽马射线爆发和超新星遗迹冲击有关的各种现象。 该项目将通过将估计的源通量与太阳背景和生物活动的最低水平进行比较，证明这些事件是否会在行星和卫星的大气层中产生非平衡光化学。 它们也可能是行星上微生物生物改变的一个有力的间歇性来源，无论是否有像臭氧这样的紫外线屏蔽。 正在研究的具体问题包括：（1）这些高能辐射源超过从太阳接收的背景通量的概率;（2）天文源中的流体力学和辐射传输，特别是在超新星的早期冲击爆发阶段;（3）当发射光谱能量分布通过模型前生物、太古代和后臭氧大气传播时，发射光谱能量分布的变换;（4）太阳系外天体如土卫六的非平衡光化学;以及（5）计算的地表通量和由于大气化学变化引起的恒星通量变化对微生物的生物效应。该项目是NSF极端环境下生命（LExEn）的一部分。资金由NSF天文科学部恒星天文&天体物理学（SAA）计划和NSF分子&细胞生物科学部（MCB）提供。