TY - JOUR
T1 - Larger Mutual Inclinations for the Shortest-period Planets
AU - Dai, Fei
AU - Masuda, Kento
AU - Winn, Joshua N.
N1 - Funding Information:
This work made use of the gaia-kepler.fun crossmatch database created by Megan Bedell. Work by F.D. and J.N.W. was supported by the Heising-Simons Foundation. Work by K.M. was performed in part under contract with the California Institute of Technology (Caltech)/Jet Propulsion Laboratory (JPL) funded by NASA through the Sagan Fellowship Program executed by the NASA Exoplanet Science Institute.
Publisher Copyright:
© 2018. The American Astronomical Society. All rights reserved..
PY - 2018/9/10
Y1 - 2018/9/10
N2 - The Kepler mission revealed a population of compact multiple-planet systems with orbital periods shorter than a year, and occasionally even shorter than a day. By analyzing a sample of 102 Kepler and K2 multiple-planet systems, we measure the minimum difference ΔI between the orbital inclinations, as a function of the orbital distance of the innermost planet. This is accomplished by fitting all the planetary signals simultaneously, constrained by an external estimate of the stellar mean density. We find ΔI to be larger when the inner orbit is smaller, a trend that does not appear to be a selection effect. We find that planets with a/R ∗ < 5 have a dispersion in ΔI of 6.°7 ± 0.°6, while planets with 5 < a/R ∗ < 12 have a dispersion of 2.°0 ± 0.°1. The planetary pairs with higher mutual inclinations also tend to have larger period ratios. These trends suggest that the shortest-period planets have experienced both inclination excitation and orbital shrinkage.
AB - The Kepler mission revealed a population of compact multiple-planet systems with orbital periods shorter than a year, and occasionally even shorter than a day. By analyzing a sample of 102 Kepler and K2 multiple-planet systems, we measure the minimum difference ΔI between the orbital inclinations, as a function of the orbital distance of the innermost planet. This is accomplished by fitting all the planetary signals simultaneously, constrained by an external estimate of the stellar mean density. We find ΔI to be larger when the inner orbit is smaller, a trend that does not appear to be a selection effect. We find that planets with a/R ∗ < 5 have a dispersion in ΔI of 6.°7 ± 0.°6, while planets with 5 < a/R ∗ < 12 have a dispersion of 2.°0 ± 0.°1. The planetary pairs with higher mutual inclinations also tend to have larger period ratios. These trends suggest that the shortest-period planets have experienced both inclination excitation and orbital shrinkage.
KW - planets and satellites: dynamical evolution and stability
KW - planets and satellites: formation
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U2 - 10.3847/2041-8213/aadd4f
DO - 10.3847/2041-8213/aadd4f
M3 - Article
AN - SCOPUS:85053382282
SN - 2041-8205
VL - 864
JO - Astrophysical Journal Letters
JF - Astrophysical Journal Letters
IS - 2
M1 - L38
ER -