Accounting for incompleteness due to transit multiplicity inKeplerplanet occurrence rates

Abstract

We investigate the role that planet detection order plays in the Kepler planet detection pipeline. The Kepler pipeline typically detects planets in order of descending signal strength (MES). We find that the detectability of transits experiences an additional 5.5% and 15.9% efficiency loss, for periods < 200 days and > 200 days respectively, when detected after the strongest signal transit in a multiple-planet system. We provide a method for determining the transit probability for multiple-planet systems by marginalizing over the empirical Kepler dataset. Furthermore, because detection efficiency appears to be a function of detection order, we discuss the sorting statistics that affect the radius and period distributions of each detection order. Our occurrence rate dataset includes radius measurement updates from the California Kepler Survey (CKS), Gaia DR2, and asteroseismology. Our population model is consistent with the results of Burke et al. (2015), but now includes an improved estimate of the multiplicity distribution. From our obtained model parameters, we find that only 4.0 ± 4.6% of solar-like GK dwarfs harbor one planet. This excess is smaller than prior studies and can be well modeled with a modified Poisson distribution, suggesting that the Kepler Dichotomy can be accounted for by including the effects of multiplicity on detection efficiency. Using our modified Poisson model we expect the average number of planets is 5.86 ± 0.18 planets per GK dwarf within the radius and period parameter space of Kepler.

Scaling K2. II. Assembly of a Fully Automated C5 Planet Candidate Catalog Using EDI-Vetter

“…This process continues until either five TCEs have been found, or the largest MES value is less than the detection threshold. Zink et al (2019a) showed that this type of masking will make higher multiplicity systems more difficult to detect, as nearby transits have the potential of being partially or fully hidden by this type of masking. However, removing the signal with a transit model is impractical.…”

“…The window function gives the probability (prob) that a certain period (P ) will meet the three transit minimum requirement for TCE consideration within the span (t span ) of the available light curve (von Braun et al 2009;Ballard et al 2010). This metric is an essential ingredient for occurrence measurements (Burke et al 2015;Zink et al 2019a;Bryson et al 2019), where all aspects of detection probability must be considered. If the data were seamless, without any masking, the equation can be found analytically:…”

Fingerprints of giant planets in the composition of solar twins

“…While this may occur in some cases, it seems unlikely to provide the explanation for the bulk of the population since essentially all of the Kepler planet hosting systems would need to have undergone dynamical instability and engulfed a planet. Dynamical instability can already be ruled out for systems with 5 or more planets (Pu & Wu 2015), which may account for more than 50 per cent of stars (Zink et al 2019) -too many for engulfment to be responsible for difference in refractory composition. Therefore, in the next section, we argue instead that the mass of dust trapped in the disc due to gap opening by the planets provides a natural explanation.…”

Forming Diverse Super-Earth Systems In Situ

“…Instead of these simple cuts, we compute the probability of detection for each planet following Burke et al (2015), who model the probability of detection using the Christiansen et al (2015Christiansen et al ( , 2016 completeness parametrization; we use the appropriate completeness function parameters for DR25. (We do not model the reduced detection efficiency of subsequent planets in the same system (Zink et al 2019) and discuss the effect on our results in Section 3.3.) See Appendix for an empirical exploration of detection efficiency.…”