Removing biases on the density of sub-Neptunes characterised via transit timing variations. Update on the mass-radius relationship of 34 Kepler planets - INSU - Institut national des sciences de l'Univers Access content directly
Journal Articles Astronomy and Astrophysics - A&A Year : 2023

Removing biases on the density of sub-Neptunes characterised via transit timing variations. Update on the mass-radius relationship of 34 Kepler planets

A. Leleu
  • Function : Author
J. -B. Delisle
  • Function : Author
S. Udry
  • Function : Author
R. Mardling
  • Function : Author
J. A. Egger
  • Function : Author
Y. Alibert
  • Function : Author
G. Chatel
  • Function : Author
P. Eggenberger
  • Function : Author
M. Stalport
  • Function : Author

Abstract

Transit timing variations (TTVs) can provide useful information on compact multi-planetary systems observed by transits by setting constraints on the masses and eccentricities of the observed planets. This is especially helpful when the host star is not bright enough for a radial velocity (RV) follow-up. However, in the past decade, a number of works have shown that TTV-characterised planets tend to have lower densities than planets characterised on the basis of RVs. Re-analysing 34 Kepler planets in the super-Earth to sub-Neptunes range using the RIVERS approach, we show that at least some of these discrepancies were due to the way transit timings were extracted from the light curve, as a result of their tendency to underestimate the TTV amplitudes. We recovered robust mass estimates (i.e. with low prior dependency) for 23 of the planets. We compared these planets the RV-characterised population and found that a large fraction of those that previously had unusually low density estimates were adjusted, allowing them to occupy a place on the mass-radius diagram much closer to the bulk of known planets. However, a slight shift toward lower densities remains, which could indicate that the compact multi-planetary systems characterised by TTVs are indeed composed of planets that are different from the bulk of the RV-characterised population. These results are especially important in the context of obtaining an unbiased view of the compact multi-planetary systems detected by Kepler, TESS, and the upcoming PLATO mission.

Data are only available at the CDS via anonymous ftp to cdsarc.cds.unistra.fr (ftp://130.79.128.5) or via https://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/669/A117

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Dates and versions

insu-03993962 , version 1 (17-02-2023)

Licence

Attribution - CC BY 4.0

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A. Leleu, J. -B. Delisle, S. Udry, R. Mardling, M. Turbet, et al.. Removing biases on the density of sub-Neptunes characterised via transit timing variations. Update on the mass-radius relationship of 34 Kepler planets. Astronomy and Astrophysics - A&A, 2023, 669, ⟨10.1051/0004-6361/202244132⟩. ⟨insu-03993962⟩
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