Occurrence conditions of the runaway greenhouse state for terrestrial exoplanets

2017 Fiscal Year Final Research Report

• Project/Area Number: 25400219
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Astronomy
• Research Institution: Hokkaido University
• Principal Investigator: Ishiwatari Masaki 北海道大学, 理学研究院, 准教授 (90271692)
• Co-Investigator(Kenkyū-buntansha): 中島 健介 九州大学, 理学研究院, 助教 (10192668)
• Project Period (FY): 2013-04-01 – 2018-03-31
• Keywords: 系外惑星 / 気候 / 同期回転惑星 / 太陽定数 / 暴走温室状態 / 大気大循環モデル / 射出限界 / 惑星半径

Outline of Final Research Achievements

For the purpose of understanding the variety of climate of terrestrial exoplanets, parameter experiments using a general circulation model were performed with various values of planetary radius, rotation rate, solar constant, solar flux distribution. With these experiments, dependence of climate state of terrestrial exoplanets on solar constant, and the occurrence condition of the runaway greenhouse state were investigated. One of the results was that, both for synchronously rotating planets and planets with Earth-like solar flux distribution including diurnal and annual change, the upper limit of outgoing longwave radiation existed and that the runaway greenhouse state emerged with global mean absorbed solar flux exceeding the upper limit of outgoing longwave radiation.

Free Research Field

惑星大気科学