Demographics of Close-In TESS Exoplanets Orbiting FGK Main-sequence Stars II. Spectral-Type Dependence and the Neptunian Landscape
Abstract
Understanding how planetary demographics depend on host star properties is essential for constraining planet formation and evolution theories. In this paper, we analyse close-in 0.5-16 d planet occurrence rates from the TESS Science Processing Operations Center (SPOC) full-frame image data for individual F-, G-, and K-type main-sequence stellar samples. Integrated over 0.5 < P < 16 d and 2 < Rp < 20 R⊕, the occurrence rates are 12.1+3.0−2.3, 10.2+1.2−1.0, and 13.1+1.4−1.2 planets per 100 stars for F-, G-, and K-type hosts, consistent with each other at 1σ, so any spectral-type dependence is localized rather than global. For transiting hot Jupiters, we measure 0.30+0.04−0.03, 0.50±0.03, and 0.67+0.08−0.07 per cent, with the rate peaking at K type; the latter being the first such measurement for K-type hosts. Modelling the Neptunian desert directly in occurrence-rate space, we find that the desert extends to longer orbital periods around hotter stars. Integrating over the desert interior gives 0.069+0.045−0.011, 0.093+0.046−0.022, and 0.150+0.033−0.026 planets per 100 stars, implying about one close-in planet in a hundred lies inside the desert, and the desert is roughly twice as populated around K- as around F-type hosts. A rigorous Bayesian model comparison for the $6−8\,R_\oplus$ strip indicates that a distinct Neptunian ridge is not required to explain the measurements.
Versions
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BibTeX
@misc{cui2026demographics,
title = {{Demographics of Close-In TESS Exoplanets Orbiting FGK Main-sequence Stars II. Spectral-Type Dependence and the Neptunian Landscape}},
author = {Kaiming Cui and David J. Armstrong and Andreas Hadjigeorghiou and Marina Lafarga and Ares Osborn and George W. King and Tim Hallatt and Vedad Kunovac and Lauren Doyle},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.31784},
eprint = {2610.31784},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.31784},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Demographics of Close-In TESS Exoplanets Orbiting FGK Main-sequence Stars II. Spectral-Type Dependence and the Neptunian Landscape
AU - Kaiming Cui
AU - David J. Armstrong
AU - Andreas Hadjigeorghiou
AU - Marina Lafarga
AU - Ares Osborn
AU - George W. King
AU - Tim Hallatt
AU - Vedad Kunovac
AU - Lauren Doyle
PY - 2026
DA - 2026/10/22
PB - arXiv
DO - 10.48550/arxiv.2610.31784
UR - https://arxiv.org/abs/2610.31784
AB - Understanding how planetary demographics depend on host star properties is essential for constraining planet formation and evolution theories. In this paper, we analyse close-in 0.5-16 d planet occurrence rates from the TESS Science Processing Operations Center (SPOC) full-frame image data for individual F-, G-, and K-type main-sequence stellar samples. Integrated over 0.5 < P < 16 d and 2 < R_p < 20 R_⊕, the occurrence rates are 12.1^+3.0_−2.3, 10.2^+1.2_−1.0, and 13.1^+1.4_−1.2 planets per 100 stars for F-, G-, and K-type hosts, consistent with each other at 1σ, so any spectral-type dependence is localized rather than global. For transiting hot Jupiters, we measure 0.30^+0.04_−0.03, 0.50±0.03, and 0.67^+0.08_−0.07 per cent, with the rate peaking at K type; the latter being the first such measurement for K-type hosts. Modelling the Neptunian desert directly in occurrence-rate space, we find that the desert extends to longer orbital periods around hotter stars. Integrating over the desert interior gives 0.069^+0.045_−0.011, 0.093^+0.046_−0.022, and 0.150^+0.033_−0.026 planets per 100 stars, implying about one close-in planet in a hundred lies inside the desert, and the desert is roughly twice as populated around K- as around F-type hosts. A rigorous Bayesian model comparison for the $6−8\,R_\oplus$ strip indicates that a distinct Neptunian ridge is not required to explain the measurements.
ER -