摘要：Abstract We present a new united theory of planet formation, which includes magneto-rotational instability (MRI) and porous aggregation of solid particles in a consistent way. We show that the “tandem planet formation” regime is likely to result in solar system-like planetary systems. In the tandem planet formation regime, planetesimals form at two distinct sites: the outer and inner edges of the MRI suppressed region. The former is likely to be the source of the outer gas giants, and the latter is the source for the inner volatile-free rocky planets. Our study spans disks with a various range of accretion rates, and we find that tandem planet formation can occur for M ˙ = 10 − 7.3 - 10 − 6.9 M ⊙ y r − 1 . The rocky planets form between 0.4–2 AU, while the icy planets form between 6–30 AU; no planets form in 2–6 AU region for any accretion rate. This is consistent with the gap in the solid component distribution in the solar system, which has only a relatively small Mars and a very small amount of material in the main asteroid belt from 2–6 AU. The tandem regime is consistent with the idea that the Earth was initially formed as a completely volatile-free planet. Water and other volatile elements came later through the accretion of icy material by occasional inward scattering from the outer regions. Reactions between reductive minerals, such as schreibersite (Fe3P), and water are essential to supply energy and nutrients for primitive life on Earth. Graphical abstract Display Omitted Highlights • The new framework of planet formation for solar system. • Magneto-rotational instability (MRI) and porous aggregation. • Planets form at the outer and inner boundaries of the MRI suppressed region. • Icy planetesimals form at the outer boundary through gravitational Instability. • Rocky particles are accumulated at the inner boundary to form terrestrial planets.
关键词：KeywordsenAccretion diskPlanet formationMagneto-rotational instabilityOrigin of life
