Updated Catalog of Kepler Planet Candidates: Focus on Accuracy and Orbital Periods

Abstract: We present a new catalog of Kepler planet candidates that prioritizes accuracy of planetary dispositions and properties over uniformity. This catalog contains 4376 transiting planet candidates, including 1791 residing within 709 multi-planet systems, and provides the best parameters available for a large sample of Kepler planet candidates. We also provide a second set of stellar and planetary properties for transiting candidates that are uniformly-derived for use in occurrence rates studies. Estimates of orbital periods have been improved, but as in previous catalogs, our tabulated values for period uncertainties do not fully account for transit timing variations (TTVs). We show that many planets are likely to have TTVs with long periodicities caused by various processes, including orbital precession, and that such TTVs imply that ephemerides of Kepler planets are not as accurate on multi-decadal timescales as predicted by the small formal errors (typically 1 part in $10^6$ and rarely $ > 10^{-5}$) in the planets' measured mean orbital periods during the Kepler epoch. Analysis of normalized transit durations implies that eccentricities of planets are anti-correlated with the number of companion transiting planets. Our primary catalog lists all known Kepler planet candidates that orbit and transit only one star; for completeness, we also provide an abbreviated listing of the properties of the two dozen non-transiting planets that have been identified around stars that host transiting planets discovered by Kepler.

• The paper presents an updated Kepler catalog with 4376 exoplanet candidates and refined orbital period estimates.
• It employs detailed analysis of transit timing variations to correct period discrepancies in multi-planet systems.
• The catalog’s refined parameters support future observations by enabling precise transit predictions and enhanced dynamical studies.

Analysis of the Updated Catalog of Planet Candidates: Focus on Accuracy and Orbital Periods

The paper by Lissauer et al. presents an updated catalog of exoplanet candidates discovered by the Kepler Space Telescope, emphasizing accuracy in classifying planetary status and refining orbital period estimates over earlier catalogs. This work marks a significant advancement in leveraging Kepler data to enhance the understanding of exoplanetary characteristics with a focus on long-term dynamical stability and transit timing variations (TTVs).

The catalog introduces 4376 transiting planet candidates, of which 1791 exist within multi-planet systems. It stands out by offering not only the standard stellar and planetary parameters but also a selection derived uniformly for specific study domains, such as occurrence rates. A significant contribution of this catalog is the improved orbital period estimates, crucial for predicting accurate future transits and facilitating dynamical studies of planetary interactions.

One of the central findings is the prevalence of TTVs in multi-planet systems, attributed to gravitational interactions, leading to non-negligible errors in period estimation if such effects are ignored. The analysis highlights that while formal period uncertainties during the Kepler mission are typically below $10^{-5}$, actual period variations driven by TTVs are often significantly larger, emphasizing the need for careful ephemeris predictions. This is crucial for both planning future observations and understanding the long-term evolution of planetary systems.

The catalog distinguishes itself by prioritizing completeness and accuracy for each planet candidate, unlike previous homogeneous methods. Notably, discrepancies between mean observational periods and long-term mean periods have been adjusted, thanks to a comprehensive understanding of TTV-induced dynamics. The exercise elucidates how these periods should be interpreted, with observations illustrating discrepancies through studies of specific systems like Kepler-11 and Kepler-80.

Another crucial aspect is the analysis of planet characteristics in multi versus single-planet systems, which continues to challenge theories of planet formation and evolution. The rarity of hot Jupiters and large-radius planets in multi-planet systems aligns with earlier findings that these giants are more prone to be solitary due to either formation mechanisms or dynamical interactions that expel neighboring planets. The catalog provides a detailed account of these patterns, offering numerical comparisons essential for theoretical models.

The detailed focus on TTVs and the improved understanding of period uncertainties is pivotal for many facets of astrophysical investigation. As planetary systems often exhibit complex gravitational interactions, this catalog not only aids in the accurate prediction of planetary transits but also provides a robust dataset for investigating tidal interactions and resonance dynamics.

The implications of this work are significant for both observational and theoretical astrophysics. Practically, it provides refined transit schedules that will be indispensable for ongoing and future missions such as TESS and PLATO. Theoretically, understanding TTVs and their role in shaping observed transit properties enriches models of planetary system formation and stability. Future developments could benefit from integrating similar methodologies into emerging datasets from other space-based observatories, maintaining the legacy of Kepler's rich contributions to exoplanet science.

In conclusion, Lissauer et al.'s updated catalog serves as a cornerstone for the continued exploration and understanding of transiting exoplanets. By refining the accuracy of detected planetary characteristics and confronting the complexities introduced by TTVs, this work not only fortifies existing knowledge but also sets a precedent for handling the intricate dynamics of planetary systems. As observational capabilities advance, these methodologies will be integral in resolving the nuances of exoplanetary dynamics and expanding the catalog of known worlds orbiting distant stars.