[P-AE16] 系外惑星

[PAE16-P08] On the origin of metal-rich close-in gas giants: planetesimals vs pebbles

*生駒 大洋^1,2、菊地 健斗¹、木村 真博¹、中山 陽史¹、柴田 翔¹ (1.東京大学 大学院理学系研究科 地球惑星科学専攻、2.国立天文台 科学研究部)

キーワード：系外惑星、形成、内部構造

According to observed mass-radius relationships for transiting exoplanets, many close-in gas giants contain large amounts of heavy elements (or metals). This fact may support the core accretion scenario for gas giant formation but brings a new challenge. Core accretion models suggest that such metals were likely injected into the gas giants after the core accretion stage. Here we explore the late accretion of metals for migrating gas giants based on two different scenarios: planetesimal accretion and pebble accretion. We show that metal-rich close-in gas giants like those detected so far can be formed under some conditions in both scenarios and, then, discuss the advantages and disadvantages of the two scenarios.