Diversity of Planetary Systems via Pebble Accretion

Astronomy Unit Seminars
Soko Matsumura
Sijme-Jan Paardekooper
March 31st, 2017 at 14:30
GO Jones Room 610

In the classical planet formation model called “core-accretion”, Jupiter-like giant planets form in two steps in a protoplanetary disc – planetary cores of several Earth masses first form via accretion of km-sized planetesimals, and then they accrete gaseous envelopes.  However, it had been unclear how to form such planetesimals without losing them to the central star.  Recently, the classical formation scenario was improved by considering the effects of “pebbles” (cm- to m-sized icy grains), which could both explain the formation of planetesimals and also speed up the core formation process.   Recently, Ida et al. (2016) presented analytical formulae for pebble accretion rates for planetary embryos larger than 100-km in size.  We have incorporated this model into an N-body code SyMBA, along with gas accretion and planet migration models, and investigated the diversity of planetary systems by varying parameters such as disc’s viscosities and masses, as well as stellar metallicities.  In this talk, I will present some of the results from our simulations.