Variability Science with the Thirty Meter Telescope

The Thirty Meter Telescope (TMT) promises transformative capabilities to time-domain stellar astrophysics, enabling precise photometric, spectroscopic and polarimetric monitoring across a broad range of variable stars. With its 30-meter aperture, diffraction-limited imaging, and advanced adaptive optics, TMT will resolve individual sources in crowded environments and push variability studies to fainter magnitudes and greater distances. Its high-resolution spectrographs and infrared instrumentation will provide powerful diagnostics of pulsations, accretion, binarity, and magnetic activity in stars from pre-main-sequence to post-AGB phases. In addition to classical stellar variability, TMT will open a new frontier in the study of atmospheric dynamics on brown dwarfs and exoplanets. Rotationally modulated variability in these objects probes heterogeneous cloud structures, while polarimetric and Doppler-resolved observations will allow mapping of surface features and constrain wind patterns. TMT’s sensitivity will extend such studies to younger and lower-mass exoplanetary companions, enabling comparative weather characterization across a broad temperature and gravity regime. These investigations will link ultracool atmospheres to fundamental questions in planetary climate physics and the formation of substellar objects and exoplanetary systems.