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The signatures of planets hosted by M dwarfs are more readily detected with transit photometry and radial velocity methods than those of planets around larger stars. Recently, transit photometry was used to discover seven planets orbiting the late-M dwarf TRAPPIST-1. Three of TRAPPIST-1s planets fall in the Habitable Zone, a region where liquid water could exist on the planetary surface given appropriate planetary conditions. We aim to investigate the habitability of the TRAPPIST-1 planets by studying the stars activity and its effect on the planets. We analyze previously-published space- and ground-based light curves and show the photometrically-determined rotation period of TRAPPIST-1 appears to vary over time due to complicated, evolving surface activity. The dramatic changes of the surface of TRAPPIST-1 suggest that rotation periods determined photometrically may not be reliable for this and similarly active stars. While the activity of the star is low, we use the premise of the cosmic shoreline to provide evidence that the TRAPPIST-1 environment has potentially led to the erosion of possible planetary atmospheres by extreme ultraviolet stellar emission.
Transiting compact multi-planet systems provide many unique opportunities to characterize the planets, including studies of size distributions, mean densities, orbital dynamics, and atmospheric compositions. The relatively short orbital periods in th
TRAPPIST-1 is a fantastic nearby (~39.14 light years) planetary system made of at least seven transiting terrestrial-size, terrestrial-mass planets all receiving a moderate amount of irradiation. To date, this is the most observationally favourable s
We construct evolutionary models of Trappist-1 in which magnetic fields impede the onset of convection according to a physics-based criterion. In the models that best fit all observational constraints, the photospheric fields in Tr-1 are found to be
The nearby (d = 12 pc) M8 dwarf star TRAPPIST-1 (2MASS J23062928-0502285) hosts a compact system of at least seven exoplanets with sizes similar to Earth. Given its importance for testing planet formation and evolution theories, and for assessing the
The early evolution of Earths atmosphere and the origin of life took place at a time when physical conditions at the Earth where radically different from its present state. The radiative input from the Sun was much enhanced in the high-energy spectra