In this talk, I will discuss a range of results from my previous work as well as my progress and plans for current and future work to characterize small exoplanets in diverse environments. First, I will report on my mass estimation and characterization of the long-period exoplanet Kepler-538b. This sub-Neptune with a period of P = 81.7 days is the only planet known to be orbiting its Sun-like star (0.892 Solar masses). By simultaneously modeling Kepler photometry and radial velocities (RVs), I find a semi-amplitude of 1.68 ± 0.39 m/s and a planet mass of 10.6 ± 2.5 Earth masses, making Kepler-538b the smallest planet beyond P = 50 days with an RV mass measurement. Next, I will discuss K2-136c, a sub-Neptune with a period of 17.3 days and the largest of three transiting planets orbiting a late-K dwarf (0.742 Solar masses) in the young Hyades open cluster (650 ± 70 Myr). Collecting and analyzing RV data from the HARPS-N and ESPRESSO spectrographs jointly with photometry from the K2 and TESS space telescopes, I find K2-136c induces a semi-amplitude of 5.46 ± 0.45 m/s, corresponding to a mass of 18.0 ± 1.7 Earth masses. K2-136c is now the smallest planet to have a measured mass in an open cluster and one of the youngest planets ever with a mass measurement. Then, I will present results from my current project to detect new planets in 914 known planetary systems using high cadence photometry from Cycle 3 of the TESS mission. I will use newly detected planets and estimated planet masses and densities to investigate multiplanet system formation and architecture. Together, these projects yield a variety of useful insights into numerous exoplanets and their place within the broader exoplanet population and provide multiple avenues for valuable future research.

Host: Rachel Fernandes

Seminar held in 538 Davey or please email CEHW-SEMINAR-QUESTIONS@lists.psu.edu to attend virtually.