The end of runaway accretion and the final mass of gas giants

Giant planets grow by accreting gas from circumstellar disks that surround young stars. Why would this process stop at a Jupiter, or any other mass? One option is that gas accretion is regulated by a gap (annular density cavity) in the disk. I will revisit this idea using modern gap-opening theory and present a closed-form expression for the final mass of gas giants. If time permits, I will also explain how this theory can be used to interpret recent observations of accreting exoplanets that are still embedded in a gas disk.