Tidal evolution of exo-planetary systems:WASP-50,GJ 1214 and CoRoT-7  

作　　者：DONG Yao JI JiangHui 

机构地区：[1]purple Mountain Observatory,Chinese Academy of Sciences,Nanjing 210008,China [2]Graduate University of Chinese Academy of Sciences,Beijing 100049,China

出　　处：《Science China(Physics,Mechanics & Astronomy)》2012年第5期872-879,共8页中国科学：物理学、力学、天文学（英文版）

基　　金：supported by the National Natural Science Foundation of China (Grant No.10973044,10833001);the Natural Science Foundation of Jiangsu Province(Grant No.BK20093411);the Foundation of Minor Planets of the Purple Mountain Observatory

摘　　要：We perform numerical simulations to investigate tidal evolution of two single-planet systems, that is, WASP-50 and GJ 1214 and a two-planet system CoRoT-7. The results of orbital evolution show that tidal decay and circularization may play a significant role in shaping their final orbits, which is related to the initial orbital data in the simulations. For GJ 1214 system, different cases of initial eccentricity are also considered as only an upper limit of its eccentricity （0.27） is shown, and the outcome suggests a possible maximum initial eccentricity （0.4） in the adopted dynamical model. Moreover, additional runs with alternative values of dissipation factor Q＇I are carried out to explore tidal evolution for GJ 1214b, and these results further indicate that the real Q＇1 of GJ 1214b may be much larger than its typical value, which may reasonably suggest that GJ 1214b bears a present-day larger eccentricity, undergoing tidal circularization at a slow rate. For the CoRoT-7 system, tidal forces make two planets migrating towards their host star as well as producing tidal circularization, and in this process tidal effects and mutual gravitational interactions are coupled with each other. Various scenarios of the initial eccentricity of the outer planet have also been done to investigate final planetary configuration. Tidal decay arising from stellar tides may still work for each system as the eccentricity decreases to zero, and this is in association with the remaining lifetime of each planet used to predict its future.We perform numerical simulations to investigate tidal evolution of two single-planet systems,that is,WASP-50 and GJ 1214 and a two-planet system CoRoT-7.The results of orbital evolution show that tidal decay and circularization may play a significant role in shaping their final orbits,which is related to the initial orbital data in the simulations.For GJ 1214 system,different cases of initial eccentricity are also considered as only an upper limit of its eccentricity(0.27) is shown,and the outcome suggests a possible maximum initial eccentricity(0.4) in the adopted dynamical model.Moreover,additional runs with alternative values of dissipation factor Q1 are carried out to explore tidal evolution for GJ 1214b,and these results further indicate that the real Q1 of GJ 1214b may be much larger than its typical value,which may reasonably suggest that GJ 1214b bears a present-day larger eccentricity,undergoing tidal circularization at a slow rate.For the CoRoT-7 system,tidal forces make two planets migrating towards their host star as well as producing tidal circularization,and in this process tidal effects and mutual gravitational interactions are coupled with each other.Various scenarios of the initial eccentricity of the outer planet have also been done to investigate final planetary configuration.Tidal decay arising from stellar tides may still work for each system as the eccentricity decreases to zero,and this is in association with the remaining lifetime of each planet used to predict its future.

关 键 词：extrasolar planets tidal decay planetary formation numerical simulations 

分 类 号：P185[天文地球—天文学] P135.3