A Uniform Search for Secondary Eclipses of Hot Jupiters in Kepler Q2 Lightcurves

Abstract

We present the results of searching the Kepler Q2 public dataset for the secondary eclipses of 76 hot Jupiter planet candidates from the list of 1,235 candidates published by Borucki et al. (2011). This search has been performed by modeling both the Kepler PDC light curves and new light curves produced via our own photometric pipeline. We derive new stellar and planetary parameters for each system with robust errors. We find 16 systems with 1-2 sigma, 14 systems with 2-3 sigma, and 6 systems with >3 sigma confidence level secondary eclipse detections in at least one light curve. We find that the majority of detected planet candidates emit more light than expected due to thermal blackbody emission in the optical Kepler bandpass, and present a trend of increasing excess emission with decreasing maximum effective planetary temperature. We explore modeling biases, significant planetary albedos, non-LTE or other thermal emission, significant internal energy generation, and exoplanet mis-identification as possible causes of both the excess emission and its correlation with expected planetary temperature. Although we find no single cause is able to explain all of the planet candidates, significant planetary albedos, with a general trend of increasing planetary albedos with decreasing atmospheric temperatures, is able to explain most of the systems. We estimate an 11% false positive rate in the current Kepler planet candidate sample of hot Jupiters. We also establish robust upper limits on the eclipse depth for all systems, and find that a significant fraction of these systems have very low albedos, significantly augmenting and extending the sample of albedo determinations to planets as cool as 1200 K. Finally, we note that continued observations with Kepler, and improved techniques for the removal of systematic noise in the Kepler data, are needed to better characterize these systems.

33 pages, 9 figures, 3 tables. Submitted to the Astronomical Journal 9/13/2011. Accepted 12/4/2011

References in corpus (18)

• Scaled solar tracks and isochrones in a large region of the Z-Y plane I. From the ZAMS to the TP-AGB end for 0.15 - 2.5 Mo stars
• Can TiO Explain Thermal Inversions in the Upper Atmospheres of Irradiated Giant Planets?
• Atmospheric Sulfur Photochemistry on Hot Jupiters
• Theoretical Spectra and Light Curves of Close-in Extrasolar Giant Planets and Comparison with Data
• Theoretical Spectral Models of the Planet HD 209458b with a Thermal Inversion and Water Emission Bands
• The phase-dependent Infrared brightness of the extrasolar planet upsilon Andromedae b
• 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
• TrES-2: The First Transiting Planet in the Kepler Field
• On the Absorption and Redistribution of Energy in Irradiated Planets
• Detection Of KOI-13.01 Using The Photometric Orbit
• Measurement of the Spin-Orbit Misalignment of KOI-13.01 from its Gravity-Darkened Kepler Transit Lightcurve
• Thermal Emission from Transiting Very-Hot Jupiters: Prospects for Ground-based Detection at Optical Wavelengths
• Ground-based secondary eclipse detection of the very-hot Jupiter OGLE-TR-56b
• Discovery and Atmospheric Characterization of Giant Planet Kepler-12b: An Inflated Radius Outlier
• SOPHIE velocimetry of Kepler transit candidates IV. KOI-196b: a non-inflated hot-Jupiter with a high albedo
• HD 75289Ab revisited - Searching for starlight reflected from a hot Jupiter
• Twenty-One New Light Curves of OGLE-TR-56b: New System Parameters and Limits on Timing Variations

Cited by in corpus (34)

• Planetary Candidates Observed by Kepler. VIII. A Fully Automated Catalog With Measured Completeness and Reliability Based on Data Release 25
• Inference of Inhomogeneous Clouds in an Exoplanet Atmosphere
• Planetary Candidates Observed by Kepler VI: Planet Sample from Q1-Q16 (47 Months)
• Planetary Candidates Observed by Kepler. VII. The First Fully Uniform Catalog Based on The Entire 48 Month Dataset (Q1-Q17 DR24)
• Thermal Phase Variations of WASP-12b: Defying Predictions
• Changing Phases of Alien Worlds: Probing Atmospheres of Kepler Planets with High-Precision Photometry
• Planetary Candidates Observed by Kepler V: Planet Sample from Q1-Q12 (36 Months)
• SOPHIE velocimetry of Kepler transit candidates VII. A false-positive rate of 35% for Kepler close-in giant exoplanet candidates
• A comprehensive study of Kepler phase curves and secondary eclipses -- temperatures and albedos of confirmed Kepler giant planets
• 3.6 and 4.5 $\mu$m $Spitzer$ Phase Curves of the Highly-Irradiated Hot Jupiters WASP-19b and HAT-P-7b
• Atmospheric Characterization of the Hot Jupiter Kepler-13Ab
• Aerosols in Exoplanet Atmospheres
• Kepler-21b: A rocky planet around a V = 8.25 magnitude star
• Kepler's Optical Secondary Eclipse of HAT-P-7b and Probable Detection of Planet-Induced Stellar Gravity Darkening
• Ks band secondary eclipses of WASP-19b and WASP-43b with the Anglo-Australian Telescope
• Kepler423b: a half-Jupiter mass planet transiting a very old solar-like star
• A study of the performance of the transit detection tool DST in space-based surveys. Application of the CoRoT pipeline to Kepler data
• Probing exoplanet clouds with optical phase curves
• Black Mirror: The impact of rotational broadening on the search for reflected light from 51 Pegasi b with high resolution spectroscopy
• Secondary eclipses in the CoRoT light curves: A homogeneous search based on Bayesian model selection
• Know the Planet, Know the Star: Precise Stellar Densities from Kepler Transit Light Curves
• Searching for reflected light from $\tau$ Bootis b with high-resolution ground-based spectroscopy: Approaching the $10^{-5}$ contrast barrier
• Spatially Resolved Modeling of Optical Albedos for a Sample of Six Hot Jupiters
• Benchmark Tests for Markov Chain Monte Carlo Fitting of Exoplanet Eclipse Observations
• Statistical Eclipses of Close-in Kepler Sub-Saturns
• An accurate mass determination for Kepler-1655b, a moderately-irradiated world with a significant volatile envelope
• Characterization of Exoplanets: Secondary Eclipses
• Average Albedos of Close-in Super-Earths and Neptunes from Statistical Analysis of Long Cadence Kepler Secondary Eclipse Data
• Supervised Learning Detection of Sixty Non-Transiting Hot Jupiter Candidates
• On the Detection of Non-Transiting Hot Jupiters in Multiple-Planet Systems
• Modeling Multi-Wavelength Stellar Astrometry. III. Determination of the Absolute Masses of Exoplanets and Their Host Stars
• Reflected-light Phase Curves with PICASO: A Kepler-7b Case Study
• The Effects of Cuboid Particle Scattering on Reflected Light Phase Curves: Insights from Laboratory Data and Theory
• Rescuing Unrecognized Exoplanet Candidates in Kepler Data