Tuning into planet formation: The tale of GJ 105.5

The Transiting Exoplanet Survey Satellite (TESS) has discovered over 5,000 planet candidates to date. One intriguing TESS sub-Neptune mass planetary candidate, GJ 105.5, has an orbital period of 15.669±0.002 days and a radius of 2.69±0.55 R_earth and orbits an adolescent K dwarf star. To both confirm the planet and constrain its mass, we obtain high-spectral resolution spectroscopy with ground-based observation with the iSHELL spectrograph at the NASA infrared telescope facility and the NEID spectrometer on the WIYN 3.5m telescope at Kitt Peak National Observatory from which we extract precise radial velocities (PRVs). Combining PRV measurements at visible and near-infrared wavelengths reduces the impact of star spots or other sources of stellar variability on the time series which can be misinterpreted as a planetary signal. In this talk, I will review the PRV method of exoplanet detection, the TESS mission, the observations obtained of this candidate planet thus far, the complex analysis needed to confirm its planetary nature, and our upcoming iSHELL and NEID observing programs. The addition of every planet with measured mass will benefit our understanding of planet formation, particularly in young systems.