REDUCED ACTIVITY AND LARGE PARTICLES FROM THE DISINTEGRATING PLANET CANDIDATE KIC 12557548b
AffiliationUniv Arizona, Steward Observ
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PublisherIOP PUBLISHING LTD
CitationREDUCED ACTIVITY AND LARGE PARTICLES FROM THE DISINTEGRATING PLANET CANDIDATE KIC 12557548b 2016, 826 (2):156 The Astrophysical Journal
JournalThe Astrophysical Journal
Rights© 2016. The American Astronomical Society. All rights reserved.
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AbstractThe intriguing exoplanet candidate KIC 12557548b is believed to have a comet-like tail of dusty debris trailing a small rocky planet. The tail of debris scatters up to 1.3% of the stellar light in the Kepler observatory's bandpass (0.42-0.9 mu m). Observing the tail's transit depth at multiple wavelengths can reveal the composition and particle size of the debris, constraining the makeup and lifetime of the sub-Mercury planet. Early dust particle size predictions from the scattering of the comet-like tail pointed toward a dust size of similar to 0.1 mu m for silicate compositions. These small particles would produce a much deeper optical transit depth than near-infrared transit depth. We measure a transmission spectrum for KIC 12557548b using the SpeX spectrograph (covering 0.8-2.4 mu m) simultaneously with the MORIS imager taking r' (0.63 mu m) photometry on the Infrared Telescope Facility for eight nights and one night in H band (1.63 mu m) using the Wide-field IR Camera at the Palomar 200 inch telescope. The infrared spectra are plagued by systematic errors, but we argue that sufficient precision is obtained when using differential spectroscopic calibration when combining multiple nights. The average differential transmission spectrum is flat, supporting findings that KIC 12557548b's debris is likely composed of larger particles greater than or similar to 0.5 mu m for pyroxene and olivine and greater than or similar to 0.2 mu m for iron and corundum. The r' photometric transit depths are all below the average Kepler value, suggesting that the observations occurred during a weak period or that the mechanisms producing optical broadband transit depths are suppressed.
VersionFinal published version
SponsorsNational Aeronautics and Space Administration [NNH14CK55B]; NASA OSS grant [NNX14AD22G]; Center for Exoplanets and Habitable Worlds at the Pennsylvania State University