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The core accretion hypothesis posits that planets with significant gaseousenvelopes accreted them from their protoplanetary discs after the formation ofrocky/icy cores. Observations indicate that such exoplanets exist at a broadrange of orbital radii, but it is not known whether they accreted theirenvelopes in situ, or originated elsewhere and migrated to their currentlocations. We consider the evolution of solid cores embedded in evolvingviscous discs that undergo gaseous envelope accretion in situ with orbitalradii in the range $0.1-10\rm au$. Additionally, we determine the long-termevolution of the planets that had no runaway gas accretion phase after discdispersal. We find: (i) Planets with $5 \rm M_{\oplus}$ cores never undergorunaway accretion. The most massive envelope contained $2.8 \rm M_{\oplus}$with the planet orbiting at $10 \rm au$. (ii) Accretion is more efficient onto$10 \rm M_{\oplus}$ and $15 \rm M_{\oplus}$ cores. For orbital radii $a_{\rm p}\ge 0.5 \rm au$, $15 \rm M_{\oplus}$ cores always experienced runaway gasaccretion. For $a_{\rm p} \ge 5 \rm au$, all but one of the $10 \rm M_{\oplus}$cores experienced runaway gas accretion. No planets experienced runaway growthat $a_{\rm p} = 0.1 \rm au$. (iii) We find that, after disc dispersal, planetswith significant gaseous envelopes cool and contract on Gyr time-scales, thecontraction time being sensitive to the opacity assumed. Our results indicatethat Hot Jupiters with core masses $\lesssim 15 \rm M_{\oplus}$ at $\lesssim0.1 \rm au$ likely accreted their gaseous envelopes at larger distances andmigrated inwards. Consistently with the known exoplanet population,Super-Earths and mini-Neptunes at small radii during the disc lifetime, accreteonly modest gaseous envelopes.

In situ accretion of gaseous envelopes on to planetary cores embedded in evolving protoplanetary discs