Kepler Mission. VIII. 285 false positives

Abstract

The Kepler mission was launched in 2009 and provided photometric data for ~200000 objects in the 105deg2 contained in the Kepler field of view (FOV; Batalha et al. 2013, Cat. J/ApJS/204/24). Each of the 95 million Kepler pixels cover 3.98*3.98'' and are designed to maximize the number of resolvable stars with magnitudes brighter than 15. There are approximately 500000 objects in the Kepler FOV that are brighter than V=16; however, only ~200000 were assigned as targets for observation, leaving many bright objects in the field unobserved. Since the main goal of Kepler is to find Earth-sized planets in the habitable zone of Sun-like stars, the targets that were chosen for observation were those with the highest potential for terrestrial planet detection. Thus, many objects in the Kepler FOV have not been observed. Due to the proximity of some of these unobserved objects to the identified targets, the possibility of contaminated signals arises. Of the observed targets, 2772 eclipsing binaries have been found and cataloged in the Kepler Eclipsing Binary Catalog (http://keplerebs.villanova.edu/; see also Kirk et al. 2016, Cat. J/AJ/151/68).

A false positive is a case where the signal from a binary object in close proximity to a target contaminates the aperture pixels, causing the target light curve to show a binary signal. This means that the incorrect object is being identified as the source of the binary signal.

Once the source of the binary signal is identified, a new light curve can be extracted. The re-extraction process is comprised of several automated steps and results in three new light curves generated for the true source of the binary signal for each quarter of available data. These light curves are generated by optimizing the signal-to-noise ratio (S/N light curve), percent eclipse depth (PED light curve), and flux eclipse depth (FED light curve). Before re-extracting the new light curves, we obtain the S/N, the PED, and the FED for the original false positive integrated aperture light curve.

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