Formation of planetary systems by pebble accretion and migration: growth of gas giants

Autor(es)

Bitsch, Bertram ^[1] ; Izidoro, Andre ^[2] ; Johansen, Anders ^[3] ; Raymond, Sean N. ^{[4, 5]} ; Morbidelli, Alessandro ^[6] ; Lambrechts, Michiel ^[3] ; Jacobson, Seth A. ^[7]

Afiliação do(s) autor(es)

^[1] Max Planck Inst Astron, Konigstuhl 17, D-69117 Heidelberg - Germany

^[2] Univ Estadual Paulista, UNESP, Grp Dinam Orbital Planetol, BR-12516410 Sao Paulo - Brazil

^[3] Lund Univ, Dept Astron & Theoret Phys, Lund Observ, S-22100 Lund - Sweden

^[4] CNRS, Lab Astrophys Bordeaux, Allee Geoffroy St Hilaire, F-33165 Pessac - France

^[5] Univ Bordeaux, Allee Geoffroy St Hilaire, F-33165 Pessac - France

^[6] Univ Nice Sophia Antipolis, CNRS, Observ Cote Azur, Lab LAGRANGE, CS 34229, F-06304 Nice 4 - France

^[7] Northwestern Univ, Dept Earth & Planetary Sci, 2145 Sheridan Rd, Evanston, IL 60208 - USA

• Tipo de documento: Artigo Científico
• Fonte: Astronomy & Astrophysics; v. 623, MAR 11 2019.
• Citações Web of Science: 12

Resumo

Giant planets migrate though the protoplanetary disc as they grow their solid core and attract their gaseous envelope. Previously, we have studied the growth and migration of an isolated planet in an evolving disc. Here, we generalise such models to include the mutual gravitational interaction between a high number of growing planetary bodies. We have investigated how the formation of planetary systems depends on the radial flux of pebbles through the protoplanetary disc and on the planet migration rate. Our N-body simulations confirm previous findings that Jupiter-like planets in orbits outside the water ice line originate from embryos starting out at 20-40 AU when using nominal type-I and type-II migration rates and a pebble flux of approximately 100-200 Earth masses per million years, enough to grow Jupiter within the lifetime of the solar nebula. The planetary embryos placed up to 30 AU migrate into the inner system (r(P) < 1 AU). There they form super-Earths or hot and warm gas giants, producing systems that are inconsistent with the configuration of the solar system, but consistent with some exoplanetary systems. We also explored slower migration rates which allow the formation of gas giants from embryos originating from the 5-10 AU region, which are stranded exterior to 1 AU at the end of the gas-disc phase. These giant planets can also form in discs with lower pebbles fluxes (50-100 Earth masses per Myr). We identify a pebble flux threshold below which migration dominates and moves the planetary core to the inner disc, where the pebble isolation mass is too low for the planet to accrete gas efficiently. In our model, giant planet growth requires a sufficiently high pebble flux to enable growth to out-compete migration. An even higher pebble flux produces systems with multiple gas giants. We show that planetary embryos starting interior to 5 AU do not grow into gas giants, even if migration is slow and the pebble flux is large. These embryos instead grow to just a few Earth masses, the mass regime of super-Earths. This stunted growth is caused by the low pebble isolation mass in the inner disc and is therefore independent of the pebble flux. Additionally, we show that the long-term evolution of our formed planetary systems can naturally produce systems with inner super-Earths and outer gas giants as well as systems of giant planets on very eccentric orbits. (AU)

• Processo FAPESP: 16/19556-7 - Formação e Dinâmica Planetária: do Sistema Solar a Exoplanetas
• Beneficiário: André Izidoro Ferreira da Costa
• Modalidade de apoio: Bolsas no Brasil - Jovens Pesquisadores
• Processo FAPESP: 16/12686-2 - Formação e dinâmica planetária: do Sistema Solar a exoplanetas
• Beneficiário: André Izidoro Ferreira da Costa
• Modalidade de apoio: Auxílio à Pesquisa - Jovens Pesquisadores