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Main Authors: Faridani, Thea, Naoz, Smadar, Li, Gongjie, Rice, Malena, Lubin, Jack
Format: Preprint
Published: 2025
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Online Access:https://arxiv.org/abs/2505.05680
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author Faridani, Thea
Naoz, Smadar
Li, Gongjie
Rice, Malena
Lubin, Jack
author_facet Faridani, Thea
Naoz, Smadar
Li, Gongjie
Rice, Malena
Lubin, Jack
contents Secular resonances in exoplanet systems occur when two or more planets have commensurabilities in the precession rates of their orbital elements, causing an exchange of angular momentum between them. The stellar gravitational quadrupole moment, which evolves over time due to stellar spin-down over the first $\sim 100\,$Myr, causes these resonances to sweep through the parameter space (of masses and semimajor-axis ratios), affecting a wider variety of systems than when spin-down is neglected. The angular momentum exchange in these resonances typically aligns the outer planets' orbits together while misaligning the innermost planet from its companions. Here, we explore how resonance-induced (mis-)alignments between planets affect the transit outcome. We use the three-planet Kepler-619 system as a concrete case study that is relatively likely (approximately $1$:$1$ odds) to have undergone a sweeping resonance. Consequently, if the outer planets are initially misaligned, a sweeping-resonance-induced push toward alignment in the outer planets' orbits substantially increases the probability that they are observed transiting together. However, the resulting misalignment of the innermost planet from its outer companions, reduces the overall probability that Kepler-619 is observed as a multi-planet transiting system when considering any pair of planets or all three together. This implies that sweeping resonances (which may occur in $20\%$ of systems) have a deleterious effect on the transiting exoplanet sample, suppressing the detection of multi-planet transiting systems in favor of apparent single-planet systems.
format Preprint
id arxiv_https___arxiv_org_abs_2505_05680
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Peekaboo: Secular Resonances from Evolving Stellar Oblateness Impede Transit Detection
Faridani, Thea
Naoz, Smadar
Li, Gongjie
Rice, Malena
Lubin, Jack
Earth and Planetary Astrophysics
Secular resonances in exoplanet systems occur when two or more planets have commensurabilities in the precession rates of their orbital elements, causing an exchange of angular momentum between them. The stellar gravitational quadrupole moment, which evolves over time due to stellar spin-down over the first $\sim 100\,$Myr, causes these resonances to sweep through the parameter space (of masses and semimajor-axis ratios), affecting a wider variety of systems than when spin-down is neglected. The angular momentum exchange in these resonances typically aligns the outer planets' orbits together while misaligning the innermost planet from its companions. Here, we explore how resonance-induced (mis-)alignments between planets affect the transit outcome. We use the three-planet Kepler-619 system as a concrete case study that is relatively likely (approximately $1$:$1$ odds) to have undergone a sweeping resonance. Consequently, if the outer planets are initially misaligned, a sweeping-resonance-induced push toward alignment in the outer planets' orbits substantially increases the probability that they are observed transiting together. However, the resulting misalignment of the innermost planet from its outer companions, reduces the overall probability that Kepler-619 is observed as a multi-planet transiting system when considering any pair of planets or all three together. This implies that sweeping resonances (which may occur in $20\%$ of systems) have a deleterious effect on the transiting exoplanet sample, suppressing the detection of multi-planet transiting systems in favor of apparent single-planet systems.
title Peekaboo: Secular Resonances from Evolving Stellar Oblateness Impede Transit Detection
topic Earth and Planetary Astrophysics
url https://arxiv.org/abs/2505.05680