Exoplanetology: Exoplanets & Exomoons

Exoplanet Occurrence Rate with Age for FGK Stars in Kepler

By Keith Cowing

Status Report

astro-ph.EP

January 24, 2025

Filed under astro-ph.EP, exoplanet, gyrochronology, isochrone, metal-rich star, planet ejection, planet-planet scattering, Stellar Cartography

Exoplanet Occurrence Rate with Age for FGK Stars in Kepler — Distribution of stellar isochrone mass (top) and spectroscopic metallicity (bottom) with isochrone (left) and gyrochronology (right) ages where the colour indicates the number of data points in each bin, with equal number of bins across the four distributions. These distributions illustrate that the two samples of isochrone and gyrochronology ages span a different parameters space in mass and metallicity despite sharing the same stars. It also shows the relationship between mass and metallicity with age which could bias the trend between occurrence rate and age. — astro-ph.EP

We measure exoplanet occurrence rate as a function of isochrone and gyrochronology ages using confirmed and candidate planets identified in Q1-17 DR25 Kepler data.

We employ Kepler’s pipeline detection efficiency to correct for the expected number of planets in each age bin. We examine the occurrence rates for planets with radii 0.2≤R_p≤20 R⊕ and orbital periods 0.2≤P≤100 days for FGK stars with ages between 1.5−8 Gyr using the inverse detection efficiency method.

We find no significant trend between occurrence rate and stellar ages; a slight, decreasing trend (within 1.5−2.5 σ) only emerges for low-mass and metal-rich stars that dominate our sample. We isolate the effects of mass and metallicity on the occurrence rate trend with age, but find the results to be inconclusive due to weak trends and small sample size.

Our results hint that the exoplanet occurrence rate may decrease over time due to dynamical instability from planet-planet scattering or planet ejection, but accurate ages and larger sample sizes are needed to resolve a clear relation between occurrence rate and age.

Maryum Sayeed, Ruth Angus, Travis Berger, Yuxi (Lucy)Lu, Jessie Christiansen, Daniel Foreman-Mackey, Melissa Ness

Comments: 13 pages, 5 figures, 2 tables. Accepted in AJ
Subjects: Earth and Planetary Astrophysics (astro-ph.EP); Solar and Stellar Astrophysics (astro-ph.SR)
Cite as: arXiv:2501.13809 [astro-ph.EP] (or arXiv:2501.13809v1 [astro-ph.EP] for this version)
https://doi.org/10.48550/arXiv.2501.13809
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Related DOI:
https://doi.org/10.3847/1538-3881/ada8a1
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Submission history
From: Maryum Sayeed
[v1] Thu, 23 Jan 2025 16:31:01 UTC (1,282 KB)
https://arxiv.org/abs/2501.13809
Astrobiology,

Keith Cowing

Explorers Club Fellow, ex-NASA Space Station Payload manager/space biologist, Away Teams, Journalist, Lapsed climber, Synaesthete, Na’Vi-Jedi-Freman-Buddhist-mix, ASL, Devon Island and Everest Base Camp veteran, (he/him) 🖖🏻

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