DIX Planetary Science Seminar

Abstract: Over the first 100 million years of their lives, planetary systems undergo major changes. Rocky planetesimals collide. Atmospheres are accreted and lost. Dynamical interactions shape and tilt planetary orbits. After providing a summary of ongoing observational efforts aimed at discovering young transiting exoplanets, I will motivate and discuss two specific questions. First: what is the youngest hot Jupiter that exists? A long-standing 10 Myr old candidate hot Jupiter, PTFO 8-8695b, might have fit the bill, but I will argue that it is probably a rare class of variable star. Combined with other recent work, the refutation of PTFO 8-8695b suggests that no hot Jupiters younger than 100 Myr have been securely identified. My second question will be: what can observations teach us about how close-in Neptunian-mass planets form and evolve? This topic will be explored through the discovery that the 40 Myr old TOI 837 probably hosts a Saturn-sized planet. The planet's host star is bright enough to enable measurements of the stellar obliquity, the planetary mass, and perhaps even the planet's outflowing atmosphere. Broadly applied, such avenues of characterization will likely improve our understanding of the processes that produce the observed exoplanet population.