An Independent Analysis of Kepler-4b through Kepler-8b

Abstract

We present two independent, homogeneous, global analyses of the transit light curves, radial velocities and spectroscopy of Kepler-4b through Kepler-8b, with numerous differences over the previous methods. These include: 1) improved decorrelated parameter fitting set, 2) new limb darkening coefficients, 3) time-stamps modified to BJD for consistency with RV, 4) two different methods for compensating for the integration-time of Kepler LC-data, 5) best-fit secondary-eclipse depths and excluded upper limits, 6) fitted mid-transit times, durations, depths and baseline fluxes for individual transits. We make several new determinations: 1) We detect a secondary eclipse for Kepler-7b of depth (47+/-14)ppm and significance 3.5-sigma. We conclude reflected light is a more plausible origin than thermal emission and determine a geometric albedo of Ag=(0.38+/-0.12). 2) An eccentric-orbit model for the Neptune-mass planet Kepler-4b is marginally detected to 2-sigma confidence with e=(0.25+/-0.12). If confirmed, this would place Kepler-4b in a similar category as GJ436b and HAT-P-11b as an eccentric, Neptune-mass planet. 3) We find marginal (2-sigma) evidence for Kepler-5b's secondary eclipse of depth (26+/-17)ppm. The most plausible explanation is reflected light caused by a planet with Ag=(0.15+/-0.10). 4) A 2.6-sigma peak in Kepler-6b TTV periodogram is detected and is not easily explained as an aliased frequency. We find that a resonant/non-resonant perturber, Trojan or exomoon all provide inadequate explanations and the most likely source is stellar rotation. 5) We find different impact parameters relative to the discovery papers in most cases, but generally self-consistent. 6) We constrain the presence of resonant planets, exomoons and Trojans using transit timing.

Revised version accepted for publication in ApJ. 34 pages, 26 figures, 12 tables

References in corpus (35)

• Achieving better than 1 minute accuracy in the Heliocentric and Barycentric Julian Dates
• DHP Framework: Digital Health Passports Using Blockchain -- Use case on international tourism during the COVID-19 pandemic
• Overview of the Kepler Science Processing Pipeline
• The Statistics of Albedo and Heat Recirculation on Hot Exoplanets
• Initial Characteristics of Kepler Long Cadence Data For Detecting Transiting Planets
• Binning is sinning: morphological light-curve distortions due to finite integration time
• Transit timing effects due to an exomoon
• HAT-P-7b: An Extremely Hot Massive Planet Transiting a Bright Star in the Kepler Field
• The Very Low Albedo of an Extrasolar Planet: MOST Spacebased Photometry of HD 209458
• Spitzer Transit and Secondary Eclipse Photometry of GJ 436b
• Analytic Approximations for Transit Light Curve Observables, Uncertainties, and Covariances
• Long Term Evolution of Close Planets Including the Effects of Secular Interactions
• The Discovery of Ellipsoidal Variations in the Kepler Light Curve of HAT-P-7
• Asteroseismic Investigation of Known Planet Hosts in the Kepler Field
• HAT-P-12b: A Low-Density Sub-Saturn Mass Planet Transiting a Metal-Poor K Dwarf
• Stability Limits in Extra-solar Planetary Systems
• Kepler-7b: A Transiting Planet with Unusually Low Density
• Investigations of approximate expressions for the transit duration
• Properties of analytic transit light curve models
• The transiting exoplanet host star GJ 436: a test of stellar evolution models in the lower main sequence, and revised planetary parameters
• Kepler-4b: Hot Neptune-Like Planet of a G0 Star Near Main-Sequence Turnoff
• Discovery and Rossiter-McLaughlin Effect of Exoplanet Kepler-8b
• Using Transit Timing Observations to Search for Trojans of Transiting Extrasolar Planets
• A Transiting Hot Jupiter Orbiting a Metal-Rich Star
• A transit timing analysis of nine RISE light curves of the exoplanet system TrES-3
• Optical Albedo Theory of Strongly-Irradiated Giant Planets: The Case of HD 209458b
• Discovery of the Transiting Planet Kepler-5b
• Polarized reflected light from the exoplanet HD189733b: First multicolor observations and confirmation of detection
• Transiting planets - lightcurve analysis for eccentric orbits
• First detection of polarized scattered light from an exoplanetary atmosphere
• A ~5 M_earth Super-Earth Orbiting GJ 436?: The Power of Near-Grazing Transits
• Nightside Pollution of Exoplanet Transit Depths
• Fast Inversion Method for Determination of Planetary Parameters from Transit Timing Variations
• Quantifying the challenges of detecting unseen planetary companions with transit timing variations
• Accuracy of stellar parameters of exoplanet-host stars determined from asteroseismology

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