Orbital Architecture of Super-Earth-Cold-Jupiter Systems from Transit Duration Ratios
Abstract
Super-Earths are commonly found with cold Jupiters, yet it is unclear whether these Super-Earth-Cold-Jupiter (SE-CJ) systems differ architecturally from other Kepler-like systems (Non-SE-CJ). One might expect the CJs to excite eccentricities and mutual inclinations among the SEs. We use two metrics: the normalized transit duration T/T0, set by the host-star density, and the pairwise duration ratio ξ between neighboring transiting planets. We find no population-level difference in T/T0 between the samples. Forward modeling of ξ, which is more directly sensitive to mutual inclinations because it isolates the impact-parameter contrast, finds no evidence that SE-CJ systems are more mutually inclined than Non-SE-CJ systems, and hints they could be even flatter. We infer a Rayleigh dispersion in mutual inclination of δ≈ 1.0∘, or a characteristic eccentricity of e ≈ 0.035 (assuming equipartition), compared with δ≈ 1.5∘ and e ≈ 0.05 for Non-SE-CJ systems. Many SE-CJ systems therefore retain nearly coplanar, low-eccentricity architectures despite hosting distant giants. We further show that secular coupling among the inner Super-Earths usually dominates over forcing from the cold Jupiter, leaving the inner planets resistant to excitation. Our analysis is limited to SE-CJ systems with multiple transiting SEs: systems in which the CJ has strongly excited the inner architecture are expected to present as single-transiting, and cannot be studied with the ξ metric. Another caveat of our result is that undetected cold Jupiters in the comparison sample could dilute the measured ξ distribution.
Related
- Prospects for detecting hot-Jupiter tidal decay through transit timing with the mission Earth 2.0
- JWST and HST Confirm Transit Timing Variations for the Ultra-Hot Jupiter TOI-2109 b
- HD 715 b, a Warm Jupiter Orbiting a Massive Subgiant Discovered from a Single TESS Transit
- ExoMOD I. A Forward Model for the Orbital Architecture of Kepler Multi-Planet Systems
- Photodynamical analysis of the TOI-4504 system: Orbital precession brings planet d into transit to reveal its deeply resonant state and similarity to GJ 876
BibTeX
@misc{lassmann2026orbital,
title = {{Orbital Architecture of Super-Earth-Cold-Jupiter Systems from Transit Duration Ratios}},
author = {Tom Lassmann and Joseph Hand and Fei Dai and Jiaxin Tang and Sharon Wang and Di-Chang Chen},
howpublished = {arXiv},
year = {2026},
month = nov,
doi = {10.48550/arxiv.2611.05963},
eprint = {2611.05963},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2611.05963},
}
RIS
TY - UNPB
TI - Orbital Architecture of Super-Earth-Cold-Jupiter Systems from Transit Duration Ratios
AU - Tom Lassmann
AU - Joseph Hand
AU - Fei Dai
AU - Jiaxin Tang
AU - Sharon Wang
AU - Di-Chang Chen
PY - 2026
DA - 2026/11/04
PB - arXiv
DO - 10.48550/arxiv.2611.05963
UR - https://arxiv.org/abs/2611.05963
AB - Super-Earths are commonly found with cold Jupiters, yet it is unclear whether these Super-Earth-Cold-Jupiter (SE-CJ) systems differ architecturally from other Kepler-like systems (Non-SE-CJ). One might expect the CJs to excite eccentricities and mutual inclinations among the SEs. We use two metrics: the normalized transit duration T/T_0, set by the host-star density, and the pairwise duration ratio ξ between neighboring transiting planets. We find no population-level difference in T/T_0 between the samples. Forward modeling of ξ, which is more directly sensitive to mutual inclinations because it isolates the impact-parameter contrast, finds no evidence that SE-CJ systems are more mutually inclined than Non-SE-CJ systems, and hints they could be even flatter. We infer a Rayleigh dispersion in mutual inclination of δ≈ 1.0^∘, or a characteristic eccentricity of e ≈ 0.035 (assuming equipartition), compared with δ≈ 1.5^∘ and e ≈ 0.05 for Non-SE-CJ systems. Many SE-CJ systems therefore retain nearly coplanar, low-eccentricity architectures despite hosting distant giants. We further show that secular coupling among the inner Super-Earths usually dominates over forcing from the cold Jupiter, leaving the inner planets resistant to excitation. Our analysis is limited to SE-CJ systems with multiple transiting SEs: systems in which the CJ has strongly excited the inner architecture are expected to present as single-transiting, and cannot be studied with the ξ metric. Another caveat of our result is that undetected cold Jupiters in the comparison sample could dilute the measured ξ distribution.
ER -