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

Petit, Antoine C. LU orcid ; Petigura, Erik A. ; Davies, Melvyn B. LU and Johansen, Anders LU (2020) In Monthly Notices of the Royal Astronomical Society 496(3). p.3101-3111
Abstract

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)

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.

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author
; ; and
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Celestial mechanics, Planets and satellites: Dynamical evolution and stability, Planets and satellites: Formation, Planets and satellites: Individual: (K2-19b, K2-19c, K2-19d)
in
Monthly Notices of the Royal Astronomical Society
volume
496
issue
3
pages
11 pages
publisher
Oxford University Press
external identifiers
  • scopus:85102148009
ISSN
0035-8711
DOI
10.1093/MNRAS/STAA1736
language
English
LU publication?
yes
id
342339d9-b9c3-42db-b3eb-fc5ee7cd92fe
date added to LUP
2021-03-22 14:32:21
date last changed
2024-03-05 23:49:25
@article{342339d9-b9c3-42db-b3eb-fc5ee7cd92fe,
  abstract     = {{<p>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.</p>}},
  author       = {{Petit, Antoine C. and Petigura, Erik A. and Davies, Melvyn B. and Johansen, Anders}},
  issn         = {{0035-8711}},
  keywords     = {{Celestial mechanics; Planets and satellites: Dynamical evolution and stability; Planets and satellites: Formation; Planets and satellites: Individual: (K2-19b, K2-19c, K2-19d)}},
  language     = {{eng}},
  number       = {{3}},
  pages        = {{3101--3111}},
  publisher    = {{Oxford University Press}},
  series       = {{Monthly Notices of the Royal Astronomical Society}},
  title        = {{Resonance in the K2-19 system is at odds with its high reported eccentricities}},
  url          = {{http://dx.doi.org/10.1093/MNRAS/STAA1736}},
  doi          = {{10.1093/MNRAS/STAA1736}},
  volume       = {{496}},
  year         = {{2020}},
}