Resonant sub-Neptunes are puffier

Article Article scientifique Lettre Resonant sub-Neptunes are puffier eng 2024-06-27 2024-06-27 author Leleu Adrien 0000-0003-2051-7974 936123 Département d'astronomie (ASTRO) author Delisle Jean-Baptiste 0000-0001-5844-9888 829407 Département d'astronomie (ASTRO) author Burn Remo 0000-0002-9020-7309 author Izidoro André author Udry Stéphane 0000-0001-7576-6236 23409 Département d'astronomie (ASTRO) author Dumusque Xavier 583253 Département d'astronomie (ASTRO) author Lovis Christophe 0000-0001-7120-5837 134919 Département d'astronomie (ASTRO) author Millholland Sarah author Parc Léna Romane Elisa 0000-0002-7382-1913 402592 Département d'astronomie (ASTRO) author Bouchy François 133687 Département d'astronomie (ASTRO) author Bourrier Vincent 0000-0002-9148-034X 828250 Département d'astronomie (ASTRO) author Alibert Yann author Faria Joao 0000-0002-6728-244X 416418 Département d'astronomie (ASTRO) author Mordasini Christoph author Segransan Damien 134301 Département d'astronomie (ASTRO) L1 10.1051/0004-6361/202450587 0004-6361 https://www.aanda.org/10.1051/0004-6361/202450587 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. Dewey 520 Swiss National Science Foundation NCCR PlanetS: Origin, evolution and characterisation of planets (phase II) 182901 CH Programmes Deutsche Forschungsgemeinschaft STRUCTURES: A unifying approach to emergent phenomena in the physical world, mathematics, and complex data 390900948 DE Exzellenzcluster (ExStra) Swiss National Science Foundation CARES-RIVERS: Characterising the Architecture of (nearly-)Resonant Exoplanetary Systems - Recognition of Interval Variations in Exoplanet Recovery Surveys. 211697 CH Programmes European Commission A SpectroPhotometric Inquiry of Close-in Exoplanets around the Desert to Understand their Nature and Evolution 947634 SPICE DUNE EU H2020 26 Département d'astronomie 12 false Astronomy & astrophysics 687 61d4740a-bc33-4270-9045-c518fcf27ca2 Article (Published version) Public Article_scientifique_from_crossref.pdf 1885652 application/pdf CC BY-4.0 ec3efab5ab50c61bf76c0d85cb6a236cc9d37795b0ef392496a6a1113754e226 openAccess Faculté des sciences / Département d'astronomie

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Resonant sub-Neptunes are puffier	Astronomy & astrophysics			2024	25	495

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Leleu, Adrien