Hubble Space Telescope High Resolution Imaging of Kepler Small and Cool Exoplanet Host Stars

Abstract

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.

Accepted for the Astronomical Journal; 13 pages with 9 figures

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Cited by in corpus (15)

• The Kepler Follow-Up Observation Program. I. A Catalog of Companions to Kepler Stars from High-Resolution Imaging
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• A Catalog of Kepler Habitable Zone Exoplanet Candidates
• Validation of Twelve Small Kepler Transiting Planets in the Habitable Zone
• Low False-Positive Rate of Kepler Candidates Estimated From A Combination Of Spitzer And Follow-Up Observations
• The Densities of Planets in Multiple Stellar Systems
• Unresolved Binary Exoplanet Host Stars Fit as Single Stars: Effects on the Stellar Parameters
• Revision of Earth-sized Kepler Planet Candidate Properties with High Resolution Imaging by Hubble Space Telescope
• Validation of small Kepler transiting planet candidates in or near the habitable zone
• Updated Catalog of Kepler Planet Candidates: Focus on Accuracy and Orbital Periods
• Stellar Companions to the Exoplanet Host Stars HD 2638 and HD 164509
• Exclusion of Stellar Companions to Exoplanet Host Stars
• Revising Properties of Planet-host Binary Systems I.: Methods and Pilot Study
• Revising Properties of Planet-host Binary Systems II: Apparent Near-Earth Analog Planets in Binaries Are Often Sub-Neptunes