• DOI:10.1038/s41550-017-0129
• Corpus ID: 54770728

A seven-planet resonant chain in TRAPPIST-1

@article{Luger2017ASR,
  title={A seven-planet resonant chain in TRAPPIST-1},
  author={Rodrigo Luger and Marko Sestovic and Ethan Kruse and Simon L. Grimm and B-O. Demory and Eric Agol and {\'E}meline Bolmont and Daniel C. Fabrycky and Catarina Silva Fernandes and Val{\'e}rie Van Grootel and Adam J. Burgasser and Micha{\"e}l Gillon and James G. Ingalls and Emmanuel Jehin and Sean N. Raymond and Franck Selsis and Amaury H. M. J. Triaud and Thomas Barclay and Geert Barentsen and Steve B. Howell and Laetitia Delrez and Julien de Wit and Daniel Foreman-Mackey and Daniel L. Holdsworth and J{\'e}r{\'e}my Leconte and Susan M. Lederer and Martin Turbet and Yaseen Almleaky and Zouhair Benkhaldoun and Pierre Magain and Brett M. Morris and Kevin Heng and Didier Queloz},
  journal={Nature Astronomy},
  year={2017},
  volume={1},
  pages={0129}
}

• R. Luger, M. Sestovic, +30 authors D. Queloz
• Published 12 March 2017
• Physics, Geology
• Nature Astronomy

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.