The Marsu Cubesat: Monitoring The Activity And Planetary Transits Of Low-Mass Stars And Young Solar Analogues

MARSU is a CubeSat mission designed to monitor transits of planetary systems around nearby M-dwarfs and young Sun-like stars, and characterize the magnetic activity of the host stars. As a dedicated infrared space photometer, MARSU is expected to be able to detect Earth-like planets in the habitable zone of M dwarfs. It will achieve continuous (duty cycle in excess of 90%) photometric monitoring in the YJH bands (1 - 1.7 mu m) for stars up to an H magnitude of 11, at a precision better than one mmag over continuous periods of up to 3 months. A heliosynchronous orbit is selected to ensure nearly continuous monitoring of stellar targets in the anti-solar direction. MARSU will include a photometric telescope occupying 1x1x3U in a 6U platform. The payload features an 8.5cm dioptric telescope with an athermal optical system and a Short-Wave InfraRed (SWIR) type detector. End-to-end simulations have been carried out and confirm that the quality of photometric data will be consistent with the primary science goals and that the subsequent technical constraints (e.g., pointing stability) are consistent with the expected performance of a 6U CubeSat. MARSU will work in parallel with SPIRou and SPIP, which are twin ground-based infrared spectropolarimeters & velocimeters operated as new generation instruments for the Canada-France-Hawaii Telescope (CFHT, Maunakea Observatory, Hawaii) and Telescope Bernard Lyot (TBL, Pic du Midi, France) respectively. The multi-source data will be analyzed together to optimize the activity filtering and exoplanet characterization (mass from the ground, radius from space).