Resonant sub-Neptunes are puffier

Fuente: arXiv
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Main Authors: Leleu, Adrien, Delisle, Jean-Baptiste, Burn, Remo, Izidoro, André, Udry, Stéphane, Dumusque, Xavier, Lovis, Christophe, Millholland, Sarah, Parc, Léna, Bouchy, François, Bourrier, Vincent, Alibert, Yann, Faria, João, Mordasini, Christoph, Ségransan, Damien
Format: Preprint
Published: 2024
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author Leleu, Adrien
Delisle, Jean-Baptiste
Burn, Remo
Izidoro, André
Udry, Stéphane
Dumusque, Xavier
Lovis, Christophe
Millholland, Sarah
Parc, Léna
Bouchy, François
Bourrier, Vincent
Alibert, Yann
Faria, João
Mordasini, Christoph
Ségransan, Damien
author_facet Leleu, Adrien
Delisle, Jean-Baptiste
Burn, Remo
Izidoro, André
Udry, Stéphane
Dumusque, Xavier
Lovis, Christophe
Millholland, Sarah
Parc, Léna
Bouchy, François
Bourrier, Vincent
Alibert, Yann
Faria, João
Mordasini, Christoph
Ségransan, Damien
contents A systematic, population-level discrepancy exists between the densities of exoplanets whose masses have been measured with transit timing variations (TTVs) versus those measured with radial velocities (RVs). Since the TTV planets are predominantly nearly resonant, it is still unclear whether the discrepancy is attributed to detection biases or to astrophysical differences between the nearly resonant and non resonant planet populations. We defined a controlled, unbiased sample of 36 sub-Neptunes characterised by Kepler, TESS, HARPS, and ESPRESSO. We found that their density depends mostly on the resonant state of the system, with a low probability (of $0.002_{-0.001}^{+0.010}$) that the mass of (nearly) resonant planets is drawn from the same underlying population as the bulk of sub-Neptunes. Increasing the sample to 133 sub-Neptunes reveals finer details: the densities of resonant planets are similar and lower than non-resonant planets, and both the mean and spread in density increase for planets that are away from resonance. This trend is also present in RV-characterised planets alone. In addition, TTVs and RVs have consistent density distributions for a given distance to resonance. We also show that systems closer to resonances tend to be more co-planar than their spread-out counterparts. These observational trends are also found in synthetic populations, where planets that survived in their original resonant configuration retain a lower density; whereas less compact systems have undergone post-disc giant collisions that increased the planet's density, while expanding their orbits. Our findings reinforce the claim that resonant systems are archetypes of planetary systems at their birth.
format Preprint
id arxiv_https___arxiv_org_abs_2406_18991
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Resonant sub-Neptunes are puffier
Leleu, Adrien
Delisle, Jean-Baptiste
Burn, Remo
Izidoro, André
Udry, Stéphane
Dumusque, Xavier
Lovis, Christophe
Millholland, Sarah
Parc, Léna
Bouchy, François
Bourrier, Vincent
Alibert, Yann
Faria, João
Mordasini, Christoph
Ségransan, Damien
Earth and Planetary Astrophysics
A systematic, population-level discrepancy exists between the densities of exoplanets whose masses have been measured with transit timing variations (TTVs) versus those measured with radial velocities (RVs). Since the TTV planets are predominantly nearly resonant, it is still unclear whether the discrepancy is attributed to detection biases or to astrophysical differences between the nearly resonant and non resonant planet populations. We defined a controlled, unbiased sample of 36 sub-Neptunes characterised by Kepler, TESS, HARPS, and ESPRESSO. We found that their density depends mostly on the resonant state of the system, with a low probability (of $0.002_{-0.001}^{+0.010}$) that the mass of (nearly) resonant planets is drawn from the same underlying population as the bulk of sub-Neptunes. Increasing the sample to 133 sub-Neptunes reveals finer details: the densities of resonant planets are similar and lower than non-resonant planets, and both the mean and spread in density increase for planets that are away from resonance. This trend is also present in RV-characterised planets alone. In addition, TTVs and RVs have consistent density distributions for a given distance to resonance. We also show that systems closer to resonances tend to be more co-planar than their spread-out counterparts. These observational trends are also found in synthetic populations, where planets that survived in their original resonant configuration retain a lower density; whereas less compact systems have undergone post-disc giant collisions that increased the planet's density, while expanding their orbits. Our findings reinforce the claim that resonant systems are archetypes of planetary systems at their birth.
title Resonant sub-Neptunes are puffier
topic Earth and Planetary Astrophysics
url https://arxiv.org/abs/2406.18991