An upper limit for the growth of inner planets?

The exotic range of known planetary systems has provoked an equally physical explanations for their diverse architectures. However, constraining formation processes requires mapping the observed exoplanet population to that which initially formed in protoplanetary disc. Numerous results suggest (internal or external) dynamical perturbation alters architectures some exoplanetary systems. Isolating planets have evolved without any can help constrain processes. We consider Kepler multiples, low mutual inclinations and are unlikely been dynamically perturbed. apply a modelling approach similar Mulders et al. (2018), additionally accounting two-dimensionality radius ($R =0.3-20\,R_\oplus$) period ($P= 0.5-730$ days) distribution. find upper limit planet mass form $M_{\rm{lim}} \propto a^\beta \exp(-a_{\rm{in}}/a)$, semi-major axis $a$ broad $a_{\rm{in}}$ $\beta$, reproduce distribution $P$, $R$ is indistinguishable from by our comparison metric. index consistent with $\beta= 1.5$, expected if growth limited accretion within Hill radius. This model favoured over models assuming separable PDF $R$. limit, extrapolated longer periods, coincident orbits RV-discovered ($a>0.2$ au, $M>1\,M_{\rm{J}}$) around recently identified density host stars, hinting at isolation growth. discuss necessary circumstances coincidental age-related bias as origin this result, concluding such possible but unlikely. conclude that, light evidence perturbed, simple during stage worth revisiting.