11:45 AM - 12:00 PM
[PAE20-11] A Climate of tidally locked terrestrial exoplanets
Keywords:Habitable exoplanets
Most of the studies for habitable planets focus on to determine the boundary of the habitable zone. From observation of exoplanet, planets with mass between the Earth and super-Earth around low-temperature star have been discussed. The rotation of such a planet is locked due to the tidal effect from the central star because they locate near the central star.
On most of the previous studies, they used one-dimensional climate models and estimated the habitable zone assuming water-rich planets, like the Earth. Recently, studies of habitable climate using a three-dimensional climate model have begun. They show that the habitable zone estimated by 3D GCM (three-dimensional general circulation model) is greatly different from that by the 1D climate model. The most important difference is the distribution of cloud in the planetary atmosphere. A terrestrial planet with liquid water on the surface around a low-temperature star has clouds in high altitude around the sub-stellar point, leading higher albedo. As a result, it can maintain a warmer climate if it is located out of the habitable zone estimated by a 1D climate model. However, when the rotation period of a planet is short enough, the pattern of the circulation changes to the super-rotation. In this case, no such clouds are formed around the sub-stellar point.
I investigate the pattern of the circulation and habitability for TRAPPIST-1 d and Proxima Centauri b. Additionally, I also investigate the effect of the distribution of water on the planetary surface on the formation of cloud.
On most of the previous studies, they used one-dimensional climate models and estimated the habitable zone assuming water-rich planets, like the Earth. Recently, studies of habitable climate using a three-dimensional climate model have begun. They show that the habitable zone estimated by 3D GCM (three-dimensional general circulation model) is greatly different from that by the 1D climate model. The most important difference is the distribution of cloud in the planetary atmosphere. A terrestrial planet with liquid water on the surface around a low-temperature star has clouds in high altitude around the sub-stellar point, leading higher albedo. As a result, it can maintain a warmer climate if it is located out of the habitable zone estimated by a 1D climate model. However, when the rotation period of a planet is short enough, the pattern of the circulation changes to the super-rotation. In this case, no such clouds are formed around the sub-stellar point.
I investigate the pattern of the circulation and habitability for TRAPPIST-1 d and Proxima Centauri b. Additionally, I also investigate the effect of the distribution of water on the planetary surface on the formation of cloud.