Past Research: Exoplanets

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The goal of this project was to calculate the occurrence of giant planets (GPs) using radial velocity (RV) data and compare it to that of Kepler's, which I found overlap well within the uncertainties. Additionally, using the Exoplanet Population Observation Simulator (EPOS), I discovered that the RV GP distribution has a turnover around the snow line. An extrapolation of this distribution out to ~100 au produces an occurrence rate that is consistent with observed direct imaging rates. This result has proven to be important since previous calculations of occurrence rates have consistently over-predicted direct imaging rates by at least an order of magnitude. This result has also shown that GPs are not always the cause of disk structures as previously thought since GPs occur far less frequently than disk structures.

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In this project, we computed the occurrence rates of planet with radii ~ 1-6 R   and periods <100 days versus planet-to-star mass ratio (q) and per stellar spectral type from the Kepler survey. We find that regardless of the spectral type, the occurrence rate can be described by a broken power-law. We also find that the position of this break and the power-law indices are the same for MGK dwarfs. Using EPOS, we find that the break in the power-law occurs at a value ~3-10 times lower than that identified by microlensing surveys (mostly low-mass stars) which implies that the most common planet inside the snow line is ∼3–10 times less massive than the one outside. With rocky planets interior to gaseous planets, the solar system broadly follows the combined mass-ratio function inferred from Kepler and microlensing.