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Title: A COMPARISON OF SPECTROSCOPIC VERSUS IMAGING TECHNIQUES FOR DETECTING CLOSE COMPANIONS TO KEPLER OBJECTS OF INTEREST

Kepler planet candidates require both spectroscopic and imaging follow-up observations to rule out false positives and detect blended stars. Traditionally, spectroscopy and high-resolution imaging have probed different host star companion parameter spaces, the former detecting tight binaries and the latter detecting wider bound companions as well as chance background stars. In this paper, we examine a sample of 11 Kepler host stars with companions detected by two techniques—near-infrared adaptive optics and/or optical speckle interferometry imaging, and a new spectroscopic deblending method. We compare the companion effective temperatures (T{sub eff}) and flux ratios (F{sub B}/F{sub A}, where A is the primary and B is the companion) derived from each technique and find no cases where both companion parameters agree within 1σ errors. In 3/11 cases the companion T{sub eff} values agree within 1σ errors, and in 2/11 cases the companion F{sub B}/F{sub A} values agree within 1σ errors. Examining each Kepler system individually considering multiple avenues (isochrone mapping, contrast curves, probability of being bound), we suggest two cases for which the techniques most likely agree in their companion detections (detect the same companion star). Overall, our results support the advantage that the spectroscopic deblending technique has for finding very close-in companionsmore » (θ ≲ 0.″02–0.″05) that are not easily detectable with imaging. However, we also specifically show how high-contrast AO and speckle imaging observations detect companions at larger separations (θ ≥ 0.″02–0.″05) that are missed by the spectroscopic technique, provide additional information for characterizing the companion and its potential contamination (e.g., position angle, separation, magnitude differences), and cover a wider range of primary star effective temperatures. The investigation presented here illustrates the utility of combining the two techniques to reveal higher-order multiples in known planet-hosting systems.« less
Authors:
 [1] ;  [2] ;  [3] ; ;  [4] ;  [5] ;  [6] ; ;  [7]
  1. Carnegie DTM, 5241 Broad Branch Road, NW, Washington, DC 20015 (United States)
  2. National Optical Astronomy Observatory, 950 N. Cherry Ave., Tucson, AZ 85719 (United States)
  3. Astronomy Department, University of California at Berkeley, Berkeley, CA 94720 (United States)
  4. NASA Exoplanet Science Institute, California Institute of Technology, 770 South Wilson Ave., Pasadena, CA 91125 (United States)
  5. Department of Physics, Southern Connecticut State University, 501 Crescent Street, New Haven, CT 06515 (United States)
  6. NASA Ames Research Center, Moffett Field, CA 94035 (United States)
  7. Department of Physics, University of Notre Dame, 225 Nieuwland Science Hall, Notre Dame, IN 46556 (United States)
Publication Date:
OSTI Identifier:
22520111
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astronomical Journal (Online); Journal Volume: 150; Journal Issue: 5; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ABSORPTION SPECTROSCOPY; COMPARATIVE EVALUATIONS; DETECTION; DIAGRAMS; EMISSION SPECTROSCOPY; INTERFEROMETRY; MAPPING; OPTICS; PLANETS; PROBABILITY; PROBES; RESOLUTION; SPACE; STARS