Abstract

Super-Earth and mini-Neptune sized planets are abundant on short orbits around solar and sub-solar mass stars. Could these planets form close to their present orbits, in the inner regions of protoplanetary discs? We investigate planet formation in the inner protoplanetary disc whose structure is governed by viscous accretion due to the magneto-rotational instability (MRI). We consider the evolution of dust in the inner disc, including growth, radial drift and fragmentation due to the MRI -induced turbulence. The inner disc becomes enhanced in dust, and we assess viability of planetesimal formation. We also consider the accretion of atmospheres onto planetary cores in the MRI -accreting gas-poor inner disc. We account for the subsequent photoevaporation of the atmospheres, and compare our results to the observed exoplanet mass-radius relationship.