The multi-telescope hot Jupiter survey: updated instrument design & performance

Exoplanet atmospheric dynamics are best probed with spectroscopic phase curves, which measure how a planet’s flux changes with longitude and orbital position to reveal heat transport. Linked properties—temperature, pressure, winds, composition, and stellar irradiation—shape clouds, hazes, and the hottest and coldest regions. Hot Jupiters, with periods under ~10 days, provide ideal laboratories for atmospheric studies, but current missions cannot obtain full phase curves for planets with periods >5 days. The Multi Telescope Hot Jupiter Survey (MiTHOS), a SMEX-class concept, will address this gap using a constellation of small satellites carrying identical spectrometers spanning 0.5–5 μm. MiTHOS will gather phase curves for over 80 hot Jupiters and use shared calibration stars to remove instrument-specific systematics. Here, we present updated optical designs and throughput estimates demonstrating MiTHOS’s ability to resolve key questions in atmospheric dynamics.