2014/01/31 by K. Masuda, Kento Masuda · 6 citations
Physics and Astronomy · #Astrophysics and Star Formation Studies #Scientific Research and Discoveries #Stellar, planetary, and galactic studies #astro-ph.EP
paper · pdf · doi:10.1088/0004-637x/783/1/53
published as Astrophys.J. 783 (2014) 53 · 9 pages, 4 figures, accepted for publication in ApJ
openalex publication_date 2014/02/12 · arxiv created 2014/02/14 · arxiv updated 2014/02/17 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/04
We present an analysis of the transit timing variations (TTVs) in the multi-transiting planetary system around Kepler-51 (KOI-620). This system consists of two confirmed transiting planets, Kepler-51b ( P b = 45.2 days) and Kepler-51c ( P c = 85.3 days), and one transiting planet candidate KOI-620.02 ( P 02 = 130.2 days), which lie close to a 1: 2: 3 resonance chain. Our analysis shows that their TTVs are consistently explained by the three-planet model, and constrains their masses as (Kepler-51b), M c = 4.0 ± 0.4 M ⊕ (Kepler-51c), and M 02 = 7.6 ± 1.1 M ⊕ (KOI-620.02), thus confirming KOI-620.02 as a planet in this system. The masses inferred from the TTVs are rather small compared to the planetary radii based on the stellar density and planet-to-star radius ratios determined from the transit light curves. Combining these estimates, we find that all three planets in this system have densities among the lowest determined, ρ p ≲ 0.05 g cm −3 . With this feature, the Kepler-51 system serves as another example of low-density compact multi-transiting planetary systems. We also identify a curious feature in the archived Kepler light curve during the double transit of Kepler-51b and KOI-620.02, which could be explained by their overlapping on the stellar disk (a planet–planet eclipse). If this is really the case, the sky-plane inclination of KOI-620.02's orbit relative to that of Kepler-51b is given by , implying significant misalignment of their orbital planes. This interpretation, however, seems unlikely because such an event that is consistent with all of the observations is found to be exceedingly rare.