Revisiting the Long-Period Transiting Planets from Kepler

Abstract

Currently, we have only limited means to probe the presence of planets at large orbital separations. Foreman-Mackey et al. searched for long-period transiting planets in the Kepler light curves using an automated pipeline. Here, we apply their pipeline, with minor modifications, to a larger sample and use updated stellar parameters from Gaia DR2. The latter boosts the stellar radii for most of the planet candidates found by FM16, invalidating a number of them as false positives. We identify 15 candidates, including two new ones. All have sizes from 0.3 to 1 $R_{\mathrm{J}}$, and all but two have periods from 2 to 10 yr. We report two main findings based on this sample. First, the planet occurrence rate for the above size and period ranges is $0.70_{-0.20}^{+0.40}$ planets per Sun-like star, with the frequency of cold Jupiters agreeing with that from radial velocity surveys. Planet occurrence rises with decreasing planet size, roughly describable as $dN/d\log R\propto R^{\alpha }$ with $\alpha =-1.6_{-0.9}^{+1.0}$, i.e., Neptune-sized planets are some four times more common than Jupiter-sized ones. Second, five out of our 15 candidates orbit stars with known transiting planets at shorter periods, including one with five inner planets. We interpret this high incidence rate to mean: (1) almost all our candidates should be genuine; (2) across a large orbital range (from $\sim 0.05$ to a few astronomical units), mutual inclinations in these systems are at most a few degrees; and (3) large outer planets exist almost exclusively in systems with small inner planets.

arXiv commentAccepted to AJ. 16 pages, 13 figures

References in corpus (49)

• emcee: The MCMC Hammer
• Gaia Data Release 2. Summary of the contents and survey properties
• The Gaia mission
• A Survey of Stellar Families: Multiplicity of Solar-Type Stars
• The PLATO 2.0 Mission
• Kepler Mission Design, Realized Photometric Performance, and Early Science
• The false positive rate of Kepler and the occurrence of planets
• batman: BAsic Transit Model cAlculatioN in Python
• Kepler Presearch Data Conditioning II - A Bayesian Approach to Systematic Error Correction
• Planetary Radii across Five Orders of Magnitude in Mass and Stellar Insolation: Application to Transits
• The Keck Planet Search: Detectability and the Minimum Mass and Orbital Period Distribution of Extrasolar Planets
• On the Unique Solution of Planet and Star Parameters from an Extrasolar Planet Transit Light Curve
• Kepler Input Catalog: Photometric Calibration and Stellar Classification
• Prevalence of Earth-size planets orbiting Sun-like stars
• Kepler Presearch Data Conditioning I - Architecture and Algorithms for Error Correction in Kepler Light Curves
• Architecture of Kepler's Multi-transiting Systems: II. New investigations with twice as many candidates
• One or more bound planets per Milky Way star from microlensing observations
• Revised Stellar Properties of Kepler Targets for the Quarter 1-16 Transit Detection Run
• False positive probabilties for all Kepler Objects of Interest: 1284 newly validated planets and 428 likely false positives
• Planetary Candidates Observed by Kepler. VIII. A Fully Automated Catalog With Measured Completeness and Reliability Based on Data Release 25
• How Dry is the Brown Dwarf Desert?: Quantifying the Relative Number of Planets, Brown Dwarfs and Stellar Companions around Nearby Sun-like Stars
• Frequency of Solar-Like Systems and of Ice and Gas Giants Beyond the Snow Line from High-Magnification Microlensing Events in 2005-2008
• Revised Radii of Kepler Stars and Planets Using Gaia Data Release 2
• Parametrizing the exoplanet eccentricity distribution with the Beta distribution
• Almost All of Kepler's Multiple Planet Candidates are Planets
• The Exoplanet Mass-Ratio Function from the MOA-II Survey: Discovery of a Break and Likely Peak at a Neptune Mass
• The Derivation, Properties and Value of Kepler's Combined Differential Photometric Precision
• About 30% of Sun-like Stars Have Kepler-like Planetary Systems: A Study of their Intrinsic Architecture
• The Kepler Follow-Up Observation Program. I. A Catalog of Companions to Kepler Stars from High-Resolution Imaging
• An Excess of Jupiter Analogs in Super-Earth Systems
• The Super Earth-Cold Jupiter Relations
• SOPHIE velocimetry of Kepler transit candidates VII. A false-positive rate of 35% for Kepler close-in giant exoplanet candidates
• Statistics of Long Period Gas Giant Planets in Known Planetary Systems
• Identification of Background False Positives from Kepler Data
• Robotic Laser-Adaptive-Optics Imaging of 715 Kepler Exoplanet Candidates using Robo-AO
• Ground-based near-UV observations of 15 transiting exoplanets: Constraints on their atmospheres and no evidence for asymmetrical transits
• Finding binaries from phase modulation of pulsating stars with Kepler: V. Orbital parameters, with eccentricity and mass-ratio distributions of 341 new binaries
• The population of long-period transiting exoplanets
• Microlensing Results Challenge the Core Accretion Runaway Growth Scenario for Gas Giants
• Measuring Transit Signal Recovery in the Kepler Pipeline II: Detection Efficiency as Calculated in One Year of Data
• Five Kepler target stars that show multiple transiting exoplanet candidates
• Planet Hunters. VIII. Characterization of 41 Long-Period Exoplanet Candidates from Kepler Archival Data
• Assessing the Effect of Stellar Companions from High-Resolution Imaging of Kepler Objects of Interest
• Transiting Planet Candidates Beyond the Snow Line Detected by Visual Inspection of 7557 Kepler Objects of Interest
• An Estimate of the Yield of Single-Transit Planetary Events from the Transiting Exoplanet Survey Satellite
• A Transiting Jupiter Analog
• Characterizing Long-Period Transiting Planets Observed by Kepler
• Robo-AO Kepler Survey V: The effect of physically associated stellar companions on planetary systems
• Transit and Radial Velocity Survey Efficiency Comparison for a Habitable Zone Earth

Cited by in corpus (29)

• Exoplanet Statistics and Theoretical Implications
• Stellar obliquities in exoplanetary systems
• A stellar mass dependence of structured disks: a possible link with exoplanet demographics
• The New Generation Planetary Population Synthesis (NGPPS). III. Warm super-Earths and cold Jupiters: A weak occurrence correlation, but with a strong architecture-composition link
• Quasi-static contraction during runaway gas accretion onto giant planets
• A significant mutual inclination between the planets within the $\pi$ Mensae system
• The TESS-Keck Survey I: A Warm Sub-Saturn-mass Planet and a Caution about Stray Light in TESS Cameras
• Mutual Orbital Inclinations Between Cold Jupiters and Inner Super-Earths
• On the patterns observed in Kepler multi-planet systems
• The TESS-Keck Survey. VIII. Confirmation of a Transiting Giant Planet on an Eccentric 261 day Orbit with the Automated Planet Finder Telescope
• Small Planets Around Cool Dwarfs: Enhanced Formation Efficiency of Super-Earths around M dwarfs
• Kojima-1Lb Is a Mildly Cold Neptune around the Brightest Microlensing Host Star
• Kepler-167e as a Probe of the Formation Histories of Cold Giants with Inner Super-Earths
• Secular chaos in white-dwarf planetary systems: origins of metal pollution and short-period planetary companions
• Super-Earths and sub-Neptunes are Insensitive to Stellar Metallicity
• Giant Outer Transiting Exoplanet Mass (GOT 'EM) Survey. I. Confirmation of an Eccentric, Cool Jupiter With an Interior Earth-sized Planet Orbiting Kepler-1514
• Prospects from TESS and Gaia to constrain the flatness of planetary systems
• The smallest planetary drivers of white dwarf pollution
• The Demographics of Wide-Separation Planets
• A 16 Hour Transit of Kepler-167 e Observed by the Ground-based Unistellar Telescope Network
• On the Degree of Dynamical Packing in the Kepler Multi-planet Systems
• Scheduling strategies for the ESPRESSO follow-up of TESS targets
• On the follow-up efforts of long-period transiting planet candidates detected with Gaia astrometry
• Discovery of a cold giant planet and mass measurement of a hot super-Earth in the multi-planetary system WASP-132
• Companion Mass Limits for 17 Binary Systems Obtained with Binary Differential Imaging and MagAO/Clio
• Search for exocomets transits in Kepler light curves: Ten new transits identified
• The SATCHEL pipeline: A general tool for data classified through citizen science
• HIP 67506 C: MagAO-X Confirmation of a New Low-Mass Stellar Companion to HIP 67506 A
• Friends and Foes: Conditional Occurrence Rates of Exoplanet Companions and their Impact on Radial Velocity Follow-up Surveys