The Relation between the Transit Depths of KIC 12557548b & the Stellar Rotation Period

Abstract

Kawahara and collaborators analyzed the transits of the candidate disintegrating Mercury-mass planet KIC 12557548b and suggested that the transit depths were correlated with the phase of the stellar rotation. We analyze the transit depths of KIC 12557548b and confirm that there is indeed a robust, statistically significant signal in the transit depths at the rotation period of the spotted host star. This signal is more prominent in the first-half of the Kepler data, and is not due to leakage of the rotating spot signal into our measurement of the transit depths, or due to unocculted starspots. We investigate the suggestion that this signal could be due to an active region on the star, emitting enhanced ultraviolet or X-ray radiation leading to an increased mass loss rate of the planet; we confirm that such a scenario could cause both modulation of the transit depths of KIC 12557548b, and small enough transit-timing variations that they might not be detected in the Kepler data. Our preferred explanation for the fact that the transit depths of KIC 12557548b are modulated with the stellar rotation phase is that the candidate transiting planet is occulting starspots on this highly spotted star; such a scenario could cause transit depth variations as large as have been observed, and cause transit-timing variations small enough that they are arguably consistent with the Kepler data.

arXiv comment14 pages, 15 figures, MNRAS, submitted August 20th, 2014

References in corpus (23)

• Kepler Mission Design, Realized Photometric Performance, and Early Science
• Kepler Presearch Data Conditioning II - A Bayesian Approach to Systematic Error Correction
• Ages for illustrative field stars using gyrochronology: viability, limitations and errors
• Kepler Presearch Data Conditioning I - Architecture and Algorithms for Error Correction in Kepler Light Curves
• HAT-P-11b: A Super-Neptune Planet Transiting a Bright K Star in the Kepler Field
• Estimation of the XUV radiation onto close planets and their evaporation
• Binning is sinning: morphological light-curve distortions due to finite integration time
• Starspots, spin-orbit misalignment, and active latitudes in the HAT-P-11 exoplanetary system
• Possible Disintegrating Short-Period Super-Mercury Orbiting KIC 12557548
• The hot-Jupiter Kepler-17b: discovery, obliquity from stroboscopic starspots, and atmospheric characterization
• Transits and Occultations of an Earth-Sized Planet in an 8.5-Hour Orbit
• How stellar activity affects the size estimates of extrasolar planets
• KOI-2700b - A Planet Candidate With Dusty Effluents on a 22-Hour Orbit
• Catastrophic Evaporation of Rocky Planets
• Transit timing variations in WASP-10b induced by stellar activity?
• The Transit Light Curve Project. XIII. Sixteen Transits of the Super-Earth GJ 1214b
• Modelling the light-curve of KIC 12557548b: an extrasolar planet with a comet like tail
• Multiwavelength Observations of the Candidate Disintegrating sub-Mercury KIC 12557548b
• The Differential Rotation of Kappa1 Ceti as Observed by MOST
• Evidence for the disintegration of KIC 12557548 b
• Kepler and Ground-based Transits of the Exo-Neptune HAT-P-11b
• Starspots - Transit Depth Relation of the Evaporating Planet Candidate KIC 12557548b
• Analysis and interpretation of 15 quarters of Kepler data of the disintegrating planet KIC 12557548 b

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• Kepler Eclipsing Binary Stars. VII. The Catalog of Eclipsing Binaries Found in the Entire Kepler Data-Set
• The K2-ESPRINT Project. I. Discovery of the Disintegrating Rocky Planet K2-22b with a Cometary Head and Leading Tail
• The Ĝ Search for Extraterrestrial Civilizations with Large Energy Supplies. IV. The Signatures and Information Content of Transiting Megastructures
• Direct evidence for an evolving dust cloud from the exoplanet KIC 12557548 b
• Photometry's bright future: Detecting Solar System analogues with future space telescopes
• Dusty tails of evaporating exoplanets. II. Physical modelling of the KIC 12557548b light curve
• Mysterious eclipses in the light-curve of KIC8462852: a possible explanation
• Inferring the Composition of Disintegrating Planet Interiors from Dust Tails with Future James Webb Space Telescope Observations
• A Transient Transit Signature Associated with the Young Star RIK-210
• Disintegrating Rocky Exoplanets
• Reduced Activity And Large Particles From the Disintegrating Planet Candidate KIC 12557548b
• A search for transit timing variations and orbital decay in WASP-46b
• A Large Ground-Based Observing Campaign of the Disintegrating Planet K2-22b
• KOI-1003: A new spotted, eclipsing RS CVn binary in the Kepler field
• Chaotic winds from a dying world: a one-dimensional map for evolving atmospheres
• Back to "Normal" for the Disintegrating Planet Candidate KIC 12557548 b
• LBT Reveals Large Dust Particles and a High Mass Loss Rate for K2-22 b
• Efficient Follow-Up of Exoplanet Transits Using Small Telescopes
• Characterization of low-mass companions to $\text{Kepler}$ objects of interest observed with APOGEE-N
• Climate Change in Hell: Long-Term Variation in Transits of the Evaporating Planet K2-22b
• Extrasolar enigmas: from disintegrating exoplanets to exoasteroids