A seven-planet resonant chain in TRAPPIST-1

Abstract : The TRAPPIST-1 system is the first transiting planet system found orbiting an ultra-cool dwarf star. At least seven planets similar to Earth in radius and in mass were previously found to transit this host star. Subsequently, TRAPPIST-1 was observed as part of the K2 mission and, with these new data, we report the measurement of an 18.764 d orbital period for the outermost planet, TRAPPIST-1h, which was unconstrained until now. This value matches our theoretical expectations based on Laplace relations and places TRAPPIST-1h as the seventh member of a complex chain, with three-body resonances linking every member. We find that TRAPPIST-1h has a radius of 0.715 Earth radii and an equilibrium temperature of 169 K, placing it at the snow line. We have also measured the rotational period of the star at 3.3 d and detected a number of flares consistent with an active, middle-aged, late M dwarf.
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Article dans une revue
Nature Astronomy, Nature Publishing Group, 2017, 1, pp.id. 0129 <10.1038/s41550-017-0129>
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Soumis le : mardi 14 mars 2017 - 11:55:45
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Rodrigo Luger, Marko Sestovic, Ethan Kruse, Simon L. Grimm, Brice-Olivier Demory, et al.. A seven-planet resonant chain in TRAPPIST-1. Nature Astronomy, Nature Publishing Group, 2017, 1, pp.id. 0129 <10.1038/s41550-017-0129>. <hal-01489220>



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