论文标题
高氮压力对宜居区和温室状态的评估的影响
The effect of high nitrogen pressures on the habitable zone and an appraisal of greenhouse states
论文作者
论文摘要
宜居区是任务体系结构利用来选择潜在可居住行星进行后续观察的主要工具。鉴于其重要性，宜居区的确切规模和位置仍然是一个热门话题，因为许多使用模型层次结构的研究都评估了各种因素，包括：大气组成，时间和行星质量。但是，很少的工作评估了可居住区如何随背景氮压力的变化而变化，后者与行星的可居住性和寿命直接相关。在这里，我使用带有云层的先进能量平衡模型，表明我们的太阳系可居住区约为0.9至1.7 au，假设在内边缘有5个杆氮背景压力和最大100％的云覆盖率。该宽度比保守的可居住区估计值约20％。计算A到M星的类似扩展。我还表明，对于绕任何恒星类型的行星来说，冷却云和高背景压力可以将失控的温室阈值温度降低到大约300 K（或更少）。这是因为行星反照率的相关增加使稳定的气候更接近恒星，在该气候下，可以从较低的平均表面温度触发快速稳定。具有很高平流层温度的行星的增强的长波发射也可以在较小的轨道距离处稳定气候。该模型预测，对于绕太阳的行星，大约330 K以上的失控温室，这与先前的工作一致。但是，潮湿的温室仅用于绕A星的行星。
The habitable zone is the main tool that mission architectures utilize to select potentially habitable planets for follow up spectroscopic observation. Given its importance, the precise size and location of the habitable zone remains a hot topic, as many studies, using a hierarchy of models, have assessed various factors including: atmospheric composition, time, and planetary mass. However, little work has assessed how the habitable zone changes with variations in background nitrogen pressure, which is directly connected to the habitability and life bearing potential of planets. Here, I use an advanced energy balance model with clouds to show that our solar system habitable zone is about 0.9 to 1.7 AU, assuming a 5 bar nitrogen background pressure and a maximum 100 percent cloud cover at the inner edge. This width is about 20 percent wider than the conservative habitable zone estimate. Similar extensions are calculated for A to M stars. I also show that cooling clouds and hazes and high background pressures can decrease the runaway greenhouse threshold temperature to approximately 300 K (or less) for planets orbiting any star type. This is because the associated increase in planetary albedo enables stable climates closer to the star, where rapid destabilization can be triggered from a lower mean surface temperature. Enhanced longwave emission for planets with very high stratospheric temperatures also permits stable climates at smaller orbital distances. The model predicts a runaway greenhouse above approximately 330 K for planets orbiting the Sun, which is consistent with previous work. However, moist greenhouses only occur for planets orbiting A-stars.
