Removing biases on the density of sub-Neptunes characterised via transit timing variations

Leleu, A.; Delisle, J.-B.; Udry, S.; Mardling, R.; Turbet, M.; Egger, J. A.; Alibert, Y.; Chatel, G.; Eggenberger, P.; Stalport, M. (2023). Removing biases on the density of sub-Neptunes characterised via transit timing variations. Astronomy and astrophysics, 669, A117. EDP Sciences 10.1051/0004-6361/202244132

aa44132-22.pdf - Published Version
Available under License Creative Commons: Attribution (CC-BY).

Download (1MB) | Preview

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.

Item Type:

Journal Article (Original Article)


?? BA4D8A311B2A4C2D86A9E8137B91AF76 ??
08 Faculty of Science > Physics Institute
08 Faculty of Science > Physics Institute > Space Research and Planetary Sciences
08 Faculty of Science > Physics Institute > NCCR PlanetS

UniBE Contributor:

Egger, Jo Ann, Alibert, Yann Daniel Pierre


500 Science > 530 Physics
500 Science > 520 Astronomy
600 Technology > 620 Engineering




EDP Sciences




Alma Hajdarevic

Date Deposited:

01 May 2023 08:39

Last Modified:

01 May 2023 08:46

Publisher DOI:





Actions (login required)

Edit item Edit item
Provide Feedback