在火星早期的氧化环境中存在液态水,这是由最近的火星探索中发现的富锰岩石推断出来的。富锰岩石所暗示的氧化气氛基本上由CO $_2$和H $_2$ O组成,没有任何还原的温室气体,如H $_2$和CH $_4$。然而,到目前为止,人们一直认为,如果没有减少温室气体的存在,早期的火星不可能足够温暖,以维持液态水的存在。在这里,我们提出H $_2$ O $_2$可能是负责加热氧化早期火星表面的气体。我们的一维大气模型表明,只有1 ppm的H $_2$ O $_2$就足以使行星表面变暖,因为它对远红外波长有很强的吸收,其中对于压力为3 bar的CO $_2$大气,地面温度可能达到273 K以上。由于在缓慢凝结条件下的快速光化学生成,潮湿和氧化的大气层预计将在其高层大气中保持足够量的H $_2$ O $_2$气体。我们的研究结果表明,在氧化的早期火星上可能保持着温暖潮湿的环境,从而表明其古老的大气氧化还原状态和可能的水环境之间可能存在联系。
英文摘要:
The existence of liquid water within an oxidized environment on early Mars has been inferred by the Mn-rich rocks found during recent explorations on Mars. The oxidized atmosphere implied by the Mn-rich rocks would basically be comprised of CO$_2$ and H$_2$O without any reduced greenhouse gases such as H$_2$ and CH$_4$. So far, however, it has been thought that early Mars could not have been warm enough to sustain water in liquid form without the presence of reduced greenhouse gases. Here, we propose that H$_2$O$_2$ could have been the gas responsible for warming the surface of the oxidized early Mars. Our one-dimensional atmospheric model shows that only 1 ppm of H$_2$O$_2$ is enough to warm the planetary surface because of its strong absorption at far-infrared wavelengths, in which the surface temperature could have reached over 273~K for a CO$_2$ atmosphere with a pressure of 3~bar. A wet and oxidized atmosphere is expected to maintain sufficient quantities of H$_2$O$_2$ gas in its upper atmosphere due to its rapid photochemical production in slow condensation conditions. Our results demonstrate that a warm and wet environment could have been maintained on an oxidized early Mars, thereby suggesting that there may be connections between its ancient atmospheric redox state and possible aqueous environment.
Proton Irradiation of Primitive Atmospheres of Young Exoplanets and early Earth: $N_{\mathrm{2}}O$ Greenhouse Warming and Prebiotic Synthesis
Yokohama National University(横滨国立大学);Institute of Science Tokyo(东京科学大学);NASA Goddard Space Flight Center(美国国家航空航天局戈达德太空飞行中心);American University(美利坚大学);Kyoto University(京都大学);Tokai-mura, Naka-gun, Ibaraki(茨城县那珂郡东海村);Tokyo City University(东京都立大学);Uppsala University(乌普萨拉大学);NASA Langley Research Center(美国国家航空航天局兰利研究中心)
A research roadmap for assessing the feasibility of warming Mars
University of Chicago(芝加哥大学);Astera Institute(Astera研究所);Los Alamos National Laboratory(洛斯阿拉莫斯国家实验室);MIT Haystack Observatory(麻省理工学院海斯塔克天文台);JPL-Caltech(加州理工学院喷气推进实验室);Harvard University(哈佛大学);Northwestern University(西北大学);Stanford University(斯坦福大学);University of Florida, Gainesville(佛罗里达大学盖恩斯维尔分校);Aeolis Research(Aeolis研究);Pioneer Labs(先锋实验室);Terraform Industries(地球化工业);University of Central Florida(中佛罗里达大学);Weill Cornell Medicine(威尔康奈尔医学院);Breakthrough Initiatives(突破计划);SynBioBeta;University of Edinburgh(爱丁堡大学)
3-D Global modelling of the early martian climate under a dense CO2+H2 atmosphere and for a wide range of surface water inventories
CO2+H2温室效应最近被认为是一个有希望的情景,足以使早期火星表面变暖,从而形成山谷网络和湖泊。在这里,我们提出了数值的3-D全球气候模拟的早期火星气候,我们已经进行了假设稠密的CO2+H2大气。我们的气候模型来自Forget et al.(2013)和Wordsworth et al.(2013)的早期工作,与火星冰川和湖泊长期演化的异步模型相结合。模拟在40°赤道进行,以研究(i)水含量和(ii)H2含量(添加到1或2巴的CO2中)如何塑造早期火星的气候和水文循环。我们表明,绝热冷却机制(华兹华斯等。2013),导致冰沉积物在寒冷的气候(所谓的“冰高地”)南部高地的积累也适用于温暖的气候,与撞击坑湖作为主要的水库。这产生的降雨主要集中在火星南部高地。如果调整(i)CO2和H2的量,(ii)水库的大小和位置,以及(iii)古老的地形(即通过删除Tharsis),模拟中的地表径流(来自降雨或融雪)的空间模式可以匹配-除了少数例外-观察到的山谷网络和撞击坑湖泊的分布。虽然我们的研究结果是在富含H2的CO2为主的大气中获得的,但它们也应该适用于评估早期火星上强大的长寿命温室气体的任何组合的影响。