The multiplicity distribution of Kepler's exoplanets
Abstract
The true multiplicity distribution of transiting planet systems is obscured by strong observational biases, leading lowmultiplicity systems to be overrepresented in the observed sample. Using the Kepler FGK planet hosts, we employ approximate Bayesian computation to infer the multiplicity distribution by comparing simulated catalogues to the observed one. After comparing a total of 10 different multiplicity distributions, half of which were twopopulation models, to the observed data, we find that a singlepopulation model following a Zipfian distribution is able to explain the Kepler data as well as any of the dichotomous models we test. Our work provides another example of a way to explain the observed Kepler multiplicities without invoking a dichotomous planet population. Using our preferred Zipfian model, we estimate that an additional 2393_{717}^{+904} planets likely reside in the 1537 FGK Kepler systems studied in this work, which would increase the planet count by a factor of 2.22_{0.36}^{+0.46}. Of these hidden worlds, 663_{151}^{+158} are expected to reside in ostensibly single transiting planet systems, meaning that an additional planet(s) is expected for approximately 1in2 such Kepler systems.
 Publication:

Monthly Notices of the Royal Astronomical Society
 Pub Date:
 November 2019
 DOI:
 10.1093/mnras/stz2350
 arXiv:
 arXiv:1907.08148
 Bibcode:
 2019MNRAS.489.3162S
 Keywords:

 methods: numerical;
 planets and satellites: dynamical evolution and stability;
 planetary systems;
 Astrophysics  Earth and Planetary Astrophysics
 EPrint:
 Submitted to MNRAS after revision from first review