High resolution imaging is an important tool for follow-up study of exoplanet
candidates found via transit detection with the Kepler Mission. We discuss here
HST imaging with the WFC3 of 23 stars that host particularly interesting Kepler
planet candidates based on their small size and cool equilibrium temperature
estimates. Results include detections, exclusion of background stars that could
be a source of false positives for the transits, and detection of
physically-associated companions in a number of cases providing dilution
measures necessary for planet parameter refinement. For six KOIs, we find that
there is ambiguity in which star hosts the transiting planet(s), with
potentially strong implications for planetary characteristics. Our sample is
evenly distributed in G, K, and M spectral types. Albeit with a small sample
size, we find that physically-associated binaries are more common than expected
at each spectral type, reaching a factor of 10 frequency excess at M. We
document the program detection sensitivities, detections, and deliverables to
the Kepler follow-up program archive.Comment: Accepted for the Astronomical Journal; 13 pages with 9 figure
