Using Potassium-40 to Study the Radiogenic Heating of Exoplanets

The radioactive decay of isotopes is an integral part of the heating of a planet's mantle, and is connected to continent formation and tectonic plate activity, which planetary scientists consider necessary for a habitable environment. One of the key isotopes that is known to drive radiogenic heating on Earth is $^{40}$K. Recently, our group constrained experimentally for the first time the destruction rate of $^{40}$K through the measurement of the $^{40}$Ar(p,n)$^{40}$K reaction rate at Ohio University. A new experiment to further constrain the destruction rate of $^{40}$K by studying the $^{37}$Cl($\alpha$,n)$^{40}$K reaction is being planned to reduce nuclear physics uncertainties in the production of $^{40}$K. In preparation, we performed post-processing reaction network calculations to estimate the sensitivity of $^{40}$K production to the relevant reaction rates. From our final results, we expect to inform studies of radiogenic heating in exoplanets.