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Title: A technique to derive improved proper motions for Kepler objects of interest

We outline an approach yielding proper motions with higher precision than exists in present catalogs for a sample of stars in the Kepler field. To increase proper-motion precision, we combine first-moment centroids of Kepler pixel data from a single season with existing catalog positions and proper motions. We use this astrometry to produce improved reduced-proper-motion diagrams, analogous to a Hertzsprung-Russell (H-R) diagram, for stars identified as Kepler objects of interest. The more precise the relative proper motions, the better the discrimination between stellar luminosity classes. Using UCAC4 and PPMXL epoch 2000 positions (and proper motions from those catalogs as quasi-Bayesian priors), astrometry for a single test Channel (21) and Season (0) spanning 2 yr yields proper motions with an average per-coordinate proper-motion error of 1.0 mas yr{sup –1}, which is over a factor of three better than existing catalogs. We apply a mapping between a reduced-proper-motion diagram and an H-R diagram, both constructed using Hubble Space Telescope parallaxes and proper motions, to estimate Kepler object of interest K-band absolute magnitudes. The techniques discussed apply to any future small-field astrometry as well as to the rest of the Kepler field.
Authors:
 [1] ;  [2] ;  [3] ;  [4]
  1. McDonald Observatory, University of Texas, Austin, TX 78712 (United States)
  2. Department of Physics and Astronomy, Mississippi State University, Starkville, MS 39762 (United States)
  3. Department of Physics and Astronomy, Vanderbilt University, Nashville, TN 37235 (United States)
  4. NASA Exoplanet Science Institute, Caltech, Pasadena, CA 91125 (United States)
Publication Date:
OSTI Identifier:
22342210
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astronomical Journal (New York, N.Y. Online); Journal Volume: 148; Journal Issue: 6; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ACCURACY; CATALOGS; COORDINATES; DIAGRAMS; DISTANCE; HERTZSPRUNG-RUSSELL DIAGRAM; LUMINOSITY; PROPER MOTION; SEASONS; SPACE; STARS; TELESCOPES