Tokano Tetsuya
Institut für Geophysik und Meteorologie, Universität zu Köln, Albertus-Magnus-Platz, 50923, Köln, Germany,
Orig Life Evol Biosph. 2015 Jun;45(1-2):231-9. doi: 10.1007/s11084-015-9424-7. Epub 2015 Mar 22.
The availability of liquid water on the surface on Earth's continents in part relies on the precipitation of water. This implies that the habitability of exomoons has to consider not only the surface temperature and atmospheric pressure for the presence of liquid water, but also the global precipitation climatology. This study explores the sensitivity of the precipitation climatology of Titan-like exomoons to these moons' orbital configuration using a global climate model. The precipitation rate primarily depends on latitude and is sensitive to the planet's obliquity and the moon's rotation rate. On slowly rotating moons the precipitation shifts to higher latitudes as obliquity is increased, whereas on quickly rotating moons the latitudinal distribution does not strongly depend on obliquity. Stellar eclipse can cause a longitudinal variation in the mean surface temperature and surface pressure between the subplanetary and antiplanetary side if the planet's obliquity and the moon's orbital distance are small. In this particular condition the antiplanetary side generally receives more precipitation than the subplanetary side. However, precipitation on exomoons with dense atmospheres generally occurs at any longitude in contrast to tidally locked exoplanets.
地球大陆表面液态水的存在部分依赖于降水。这意味着系外卫星的宜居性不仅要考虑液态水存在时的表面温度和大气压力,还要考虑全球降水气候学。本研究使用全球气候模型探讨了类土卫六系外卫星的降水气候学对这些卫星轨道构型的敏感性。降水率主要取决于纬度,并且对行星的倾角和卫星的自转速率敏感。在自转缓慢的卫星上,随着倾角增加,降水向高纬度转移,而在自转快速的卫星上,纬度分布并不强烈依赖于倾角。如果行星的倾角和卫星的轨道距离较小,恒星日食会导致行星向日面和背日面之间平均表面温度和表面压力的纵向变化。在这种特殊情况下,背日面通常比行星向日面接收更多降水。然而,与潮汐锁定的系外行星不同,大气层浓厚的系外卫星上的降水通常在任何经度都会发生。