17:15 〜 18:45
[PPS07-P22] 地球質量惑星の形成論
キーワード：地球型惑星、重力トルク、惑星形成論、原始太陽系円盤、磁気回転不安定
We show a new terrestrial planets formation theory, which make clear that planets of Earth-size mass generate inevitably in tandem protosolar disk. Tandem protosolar disk based on Tandem planet formation theory (e.g., Ebisuzaki and Imaeda 2017) taking into account of the magneto-rotational instability (MRI) (e.g., Balbus and Hawley 1991; Hawley and Balbus 1991), porous aggregation (Kataoka et al. 2013; Okuzumi et al. 2012) and radial drift of the solid particles (e.g., Whipple 1972; Adachi et al. 1976; Weidenschilling 1977).
Tandem protosolar disk consists of three regions, the inner turbulent region (ITR), the magneto-rotational instability (MRI) suppressed region (MSR), and the outer turbulent region (OTR). The solid particles accumulate and planetesimal form just inner MRI front between ITR and MSR, and outer MRI front between MSR and OTR. The former is likely to be the source of inner rocky planets and the later outer gas giants. When the planetesimal grow up to Earth-size mass in inner edges of the MRI suppressed region, move to outside radial by torque of gas (Lyra et al. 2010; Paardekooper 2014; Paardekooper et al. 2010; Paardekooper and Papaloizou 2009).
We show the terrestrial planet formation proceeds as follows. 1) The first planet is formed by gravitational instability and grows by the pebbles accretion (Cuzzi et al. 1993). 2) When the planet become massive enough, it migrates out from the inner MRI front by gravitational torque (Lyra et al. 2010; Paardekooper 2014; Paardekooper et al. 2010; Paardekooper and Papaloizou 2009). 3) The second planet is immediately formed by gravitational instability, if there remain solid particles still in the inner MRI front. This process 1-3 is repeated, until solid particles are completely used up. When the protosolar disk accretion rate of M=10-7.08 M⊕yr-1, the total mass of solid materials at inner edges of the MRI is 1.99 M⊕, and two planets with the mass close to the Earth mass are produced. It is similar to the solar system (Earth and Venus), which are account for 92% in its terrestrial planets. We show that mass of terrestrial planets are inevitable in solar system.
Tandem protosolar disk consists of three regions, the inner turbulent region (ITR), the magneto-rotational instability (MRI) suppressed region (MSR), and the outer turbulent region (OTR). The solid particles accumulate and planetesimal form just inner MRI front between ITR and MSR, and outer MRI front between MSR and OTR. The former is likely to be the source of inner rocky planets and the later outer gas giants. When the planetesimal grow up to Earth-size mass in inner edges of the MRI suppressed region, move to outside radial by torque of gas (Lyra et al. 2010; Paardekooper 2014; Paardekooper et al. 2010; Paardekooper and Papaloizou 2009).
We show the terrestrial planet formation proceeds as follows. 1) The first planet is formed by gravitational instability and grows by the pebbles accretion (Cuzzi et al. 1993). 2) When the planet become massive enough, it migrates out from the inner MRI front by gravitational torque (Lyra et al. 2010; Paardekooper 2014; Paardekooper et al. 2010; Paardekooper and Papaloizou 2009). 3) The second planet is immediately formed by gravitational instability, if there remain solid particles still in the inner MRI front. This process 1-3 is repeated, until solid particles are completely used up. When the protosolar disk accretion rate of M=10-7.08 M⊕yr-1, the total mass of solid materials at inner edges of the MRI is 1.99 M⊕, and two planets with the mass close to the Earth mass are produced. It is similar to the solar system (Earth and Venus), which are account for 92% in its terrestrial planets. We show that mass of terrestrial planets are inevitable in solar system.