Evolutionary climate tracks of Earth-like planets
Evolutionary climate tracks of Earth-like planets
复制标题
类地行星的气候演化轨迹
DOI：
10.1088/2041-8205/815/1/l7
复制
发表时间：
2015
期刊：
影响因子：
--
通讯作者：
E.
中科院分区：
文献类型：
--
作者：
Kadoya;S. & Tajika;E.
最近的研究表明，除了日照外，二氧化碳脱气率是导致类地行星气候的一个重要限制因素。由于行星内部的热演化，co2脱气速率应随时间变化。本文采用地幔脱气模型与参数化对流模型相结合的方法，对具有不同质量和距离中心恒星的类地行星的气候演化进行了估计。由于地幔温度的降低，co2脱气速率随时间单调降低。大行星的CO 2脱气率高于小行星，因为大行星的内部比小行星的内部更热。然而，由于不同大小和陆地/海洋比与地球相似的行星之间的表面积差异所产生的硅酸盐风化速率的差异，可以补偿co2脱气速率差异所产生的影响。这些结果表明，与行星质量无关，大多数位于旧行星系统宜居带（HZs）外围区域的类地行星处于“雪球”气候模式（即在雪球和温暖状态之间振荡）。因为雪球状态持续的时间比温暖的气候状态长得多，所以在年老恒星周围的hz中，类地行星在统计上被观察到为“雪球行星”。
Recent studies have revealed that, in addition to insolation, the CO 2 degassing rate is an important limiting factor on the resulting climate of Earth-like planets. The CO 2 degassing rate should change with time owing to the thermal evolution of planetary interiors. Here we use a mantle degassing model coupled with a parameterized convection model to estimate the climatic evolution of Earth-like planets with different masses and distances from their central stars. The CO 2 degassing rate decreases monotonically with time owing to the decreasing mantle temperature. The CO 2 degassing rate for large planets is higher than that for small planets because the interiors of large planets are hotter than those of small planets. However, the effects arising from the difference in CO 2 degassing rate could be compensated by the difference in the silicate weathering rate derived from the difference in the surface area among planets with different size and with a similar land/sea ratio as the Earth. These results indicate that most of the Earth-like planets in the outer regions of the habitable zones (HZs) of old planetary systems are in the" snowball" climate mode (ie, oscillating between snowball and warm states), irrespective of planetary mass. Because the snowball state lasts much longer than the warm climate state, Earth-like planets in HZs around old stars would statistically be observed as" snowball planets."