Science Results from the Tierras Observatory: The Wonders of Night-to-Night Photometric Stability with Juliana Garcia-Mejia

The Tierras Observatory is a refurbished 1.3-m facility at Whipple Observatory designed for ultra-precise time-series photometry of M dwarfs. Its custom 40-nm filter centered at 864 nm, combined with a deep-depletion frame-transfer CCD, enables stable photometry at the few-hundred-ppm level over multi-month baselines. After demonstrating this stability on nearby low-mass stars, Tierras has transitioned into a productive science facility: constraining stellar rotation periods, measuring precise ephemerides of TESS planets, and enabling discoveries ranging from resonant sub-Neptunes around HD 110067 to a warm Jupiter around TOI-4641. Ongoing campaigns are targeting the lowest-mass M dwarfs to search for long-period terrestrial planets, leveraging Tierras’s stability to reveal small signals inaccessible to TESS alone.