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Anders Johansen. Profile picture.

Anders Johansen

Professor

Anders Johansen. Profile picture.

Resonance in the K2-19 system is at odds with its high reported eccentricities

Author

  • Antoine C. Petit
  • Erik A. Petigura
  • Melvyn B. Davies
  • Anders Johansen

Summary, in English

K2-19 hosts a planetary system composed of two outer planets, b and c, with size of 7.0 ± 0.2 R⊕ and 4.1 ± 0.2 R⊕, and an inner planet, d, with a radius of 1.11 ± 0.05 R® A recent analysis of Transit-Timing Variations (TTVs) suggested b and c are close to but not in 3:2 mean motion resonance (MMR) because the classical resonant angles circulate. Such an architecture challenges our understanding of planet formation. Indeed, planet migration through the protoplanetary disc should lead to a capture into the MMR. Here, we show that the planets are in fact, locked into the 3:2 resonance despite circulation of the conventional resonant angles and aligned periapses. However, we show that such an orbital configuration cannot be maintained for more than a few hundred million years due to the tidal dissipation experienced by planet d. The tidal dissipation remains efficient because of a secular forcing of the innermost planet eccentricity by planets b and c. While the observations strongly rule out an orbital solution where the three planets are on close to circular orbits, it remains possible that a fourth planet is affecting the TTVs such that the four planet system is consistent with the tidal constraints.

Department/s

  • Lund Observatory
  • eSSENCE: The e-Science Collaboration

Publishing year

2020

Language

English

Pages

3101-3111

Publication/Series

Monthly Notices of the Royal Astronomical Society

Volume

496

Issue

3

Document type

Journal article

Publisher

Oxford University Press

Topic

  • Astronomy, Astrophysics and Cosmology

Keywords

  • Celestial mechanics
  • Planets and satellites: Dynamical evolution and stability
  • Planets and satellites: Formation
  • Planets and satellites: Individual: (K2-19b, K2-19c, K2-19d)

Status

Published

ISBN/ISSN/Other

  • ISSN: 0035-8711