Abstract

Theoretical studies of the last decade established that massive protostellar/protoplanetary discs larger than about 50 AU give birth to massive (about 10 Jupiter mass) gas clumps. These clumps were thought to contract into massive planets or brown dwarfs, and perhaps explain a handful of large separation giant exoplanets. However, recent numerical simulations (by 5 independent groups so far) show that these clumps migrate inwards rapidly. Significantly, the clumps may migrate faster than they contract, thus getting tidally destroyed before they make a WD or a giant planet. Tidal disruption remnants are not uninteresting—these are terrestrial-like planets and asteroids-like bodies. This upgrade to the disc instability model makes it potentially possible for the model to provide an alternative (to core accretion) explanation for all types of exoplanets and the Solar System (Boley et al 2010, Nayakshin 2010). Clearly, quantitative and detailed modelling of these processes is required to assess the true potential of the model. We present some of the steps that we have taken into this direction, addressing FU Ori outbursts of protostars, “hot super earth” exoplanets, and some of the structure of the Solar System.