A&A 613, A37 (2018) https://doi.org/10.1051/0004-6361/201731992 Astronomy & © ESO 2018 Astrophysics Interior structures and tidal heating in the TRAPPIST-1 planets Amy C. Barr1, Vera Dobos2,3,4, and László L. Kiss2,5 1 Planetary Science Institute, 1700 E. Ft. Lowell, Suite 106, Tucson, AZ 85719, USA e-mail:
[email protected] 2 Konkoly Thege Miklós Astronomical Institute, Research Centre for Astronomy and Earth Sciences, Hungarian Academy of Sciences, 1121 Konkoly Thege Miklós út 15–17, Budapest, Hungary 3 Geodetic and Geophysical Institute, Research Centre for Astronomy and Earth Sciences, Hungarian Academy of Sciences, 9400 Csatkai Endre u. 6–8, Sopron, Hungary 4 ELTE Eötvös Loránd University, Gothard Astrophysical Observatory, Szombathely, Szent Imre h. u. 112, Hungary 5 Sydney Institute for Astronomy, School of Physics A28, University of Sydney, NSW 2006, Australia Received 25 September 2017 / Accepted 14 December 2017 ABSTRACT Context. With seven planets, the TRAPPIST-1 system has among the largest number of exoplanets discovered in a single system so far. The system is of astrobiological interest, because three of its planets orbit in the habitable zone of the ultracool M dwarf. Aims. We aim to determine interior structures for each planet and estimate the temperatures of their rock mantles due to a balance between tidal heating and convective heat transport to assess their habitability. We also aim to determine the precision in mass and radius necessary to determine the planets’ compositions. Methods. Assuming the planets are composed of uniform-density noncompressible materials (iron, rock, H2O), we determine possible compositional models and interior structures for each planet.