Princeton University Extrasolar Planet Discussion Group
The Epoch of Giant Planet Migration: Searching for Young Planets within the Noise
The presence of close-in giant planets indicates that inward orbital migration is a common phenomenon. However, the processes by which these gas giants arrived at their locations are poorly constrained as radial velocity (RV) surveys have largely avoided young stars. Young stars have intrinsic astrophysical RV "jitter" primarily driven by rotationally-modulated starspots which can overwhelm planetary signals at visible wavelengths. Fortunately, moving into the near-infrared (NIR) has been shown to reduce this variability. I am carrying out a large precision RV survey of intermediate-age (20-200 Myr) GK dwarfs in young moving groups with the Habitable Zone Planet Finder (HPF), a stabilized high resolution, NIR spectrograph located at the Hobby-Eberly Telescope. This program will clarify the timescale and dominant physical mechanism of giant planet migration by measuring their occurrence rate at young ages and comparing them to established frequencies at older ages. In this talk, I will summarize the survey design and initial results, including an overview of the first candidate planets to emerge from this program. Furthermore, I will discuss my adopted stellar activity mitigation schemes for these candidates and also present a novel GP framework that can simultaneously model activity-based variability in both photometric and RV time series. For synthetic data sets with simulated starspot contamination, this new method improves residual scatter from predicting stellar activity signals as compared to other GP techniques, facilitating the possibility of finding giant planets around young stars.