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Hauptverfasser: Tu, Pei-Wei, Xie, Ji-Wei, Chen, Di-Chang, Zhou, Ji-Lin
Format: Preprint
Veröffentlicht: 2025
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Online-Zugang:https://arxiv.org/abs/2504.20986
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author Tu, Pei-Wei
Xie, Ji-Wei
Chen, Di-Chang
Zhou, Ji-Lin
author_facet Tu, Pei-Wei
Xie, Ji-Wei
Chen, Di-Chang
Zhou, Ji-Lin
contents Ultra-short-period (USP) planets, with orbital periods shorter than one day, represent a unique class of exoplanets whose origin remains puzzling. Determining their age distribution and temporal evolution is vital for uncovering their formation and evolutionary pathways. Using a sample of over 1,000 short-period planets around Sun-like stars, we find that the host stars of USP planets are relatively older and have a higher prevalence in the Galactic thick disk compared to stars hosting other short-period planets. Furthermore, we find that the occurrence of USP planets increases with stellar age and uncover evidence indicating that USP planetary system architectures evolve on Gyr timescales. This includes a distinct dip-pileup in period distributions around ~1 day and an expansion of orbital spacings with time. In addition, younger USP planet systems are observed to have fewer multiple transiting planets, implying fewer nearby companions and/or larger mutual orbital inclinations. Our findings suggest that USP planets continuously form through inward migration driven by tidal dissipation over Gyr timescales, and that younger and older USP planets may have originated via different specific tidal migration pathways.
format Preprint
id arxiv_https___arxiv_org_abs_2504_20986
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Planets Across Space and Time (PAST). VI. Age Dependence of the Occurrence and Architecture of Ultra-Short-Period Planet Systems
Tu, Pei-Wei
Xie, Ji-Wei
Chen, Di-Chang
Zhou, Ji-Lin
Earth and Planetary Astrophysics
Ultra-short-period (USP) planets, with orbital periods shorter than one day, represent a unique class of exoplanets whose origin remains puzzling. Determining their age distribution and temporal evolution is vital for uncovering their formation and evolutionary pathways. Using a sample of over 1,000 short-period planets around Sun-like stars, we find that the host stars of USP planets are relatively older and have a higher prevalence in the Galactic thick disk compared to stars hosting other short-period planets. Furthermore, we find that the occurrence of USP planets increases with stellar age and uncover evidence indicating that USP planetary system architectures evolve on Gyr timescales. This includes a distinct dip-pileup in period distributions around ~1 day and an expansion of orbital spacings with time. In addition, younger USP planet systems are observed to have fewer multiple transiting planets, implying fewer nearby companions and/or larger mutual orbital inclinations. Our findings suggest that USP planets continuously form through inward migration driven by tidal dissipation over Gyr timescales, and that younger and older USP planets may have originated via different specific tidal migration pathways.
title Planets Across Space and Time (PAST). VI. Age Dependence of the Occurrence and Architecture of Ultra-Short-Period Planet Systems
topic Earth and Planetary Astrophysics
url https://arxiv.org/abs/2504.20986