| Abstract: | 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. |