Confusion limited surveys: using WISE to quantify the rarity of warm dust around Kepler stars

摘要: We describe a search for infra-red excess emission from dusty circumstellar material around 180,000 stars observed by the Kepler and WISE missions. This study is motivated i) potential to find bright warm disks planet host stars, ii) need characterise distribution of rare disks, iii) possible identification candidates discovering transiting dust concentrations. about 8,000 that have emission, mostly at 12um. The positions these correlate with 100um background level so most flux measurements associated excesses are spurious. identify 271 plausible making 5MJy/sr cut in IRAS emission. number counts excesses, both 12 22um, same as extra-Galactic counts. Thus, although some may be circumstellar, can explained chance alignments galaxies. one exception 22um relatively nearby A-type star we were able confirm because disk occurrence rate independent stellar distance. Despite our low detection rate, results place valuable upper limits on large mid-infrared excesses; e.g. fewer than 1:1000 12um (F_ obs/F_star) larger factor five. In contrast previous studies, no evidence 1790 candidate planets (we attribute significant galaxy), hosts different bulk population. Higher resolution imaging best way rule out galaxy confusion more reliable among stars. A similar survey ours focusses would well suited finding disks.