The Habitable-zone Planet Finder Detects a Terrestrial-mass Planet Candidate Closely Orbiting Gliese 1151: The Likely Source of Coherent Low-frequency Radio Emission from an Inactive Star

The coherent low-frequency radio emission detected by LOFAR from Gliese 1151, a quiescent M4.5 dwarf star, has properties consistent with theoretical expectations of star-planet interactions for an Earth-sized planet on 1-5 day orbit. New near-infrared radial velocities the Habitable-zone Planet Finder (HPF) spectrometer 10m Hobby-Eberly Telescope at McDonald Observatory, combined previous HARPS-N, reveal periodic Doppler signature $m\sin i = 2.5 \pm 0.5 M_\oplus$ exoplanet 2.02-day Precise photometry Transiting Exoplanet Survey Satellite (TESS) shows no flares or activity signature, M dwarf. While planetary transit is in TESS data, weak photometric modulation detectable $\sim2$ period. This independent detection candidate signal radial-velocity technique adds further weight to claim first star-exoplanet wavelengths, and helps validate this emerging exoplanets.