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Title: Limits on stellar companions to exoplanet host stars with eccentric planets

Though there are now many hundreds of confirmed exoplanets known, the binarity of exoplanet host stars is not well understood. This is particularly true of host stars that harbor a giant planet in a highly eccentric orbit since these are more likely to have had a dramatic dynamical history that transferred angular momentum to the planet. Here we present observations of four exoplanet host stars that utilize the excellent resolving power of the Differential Speckle Survey Instrument on the Gemini North telescope. Two of the stars are giants and two are dwarfs. Each star is host to a giant planet with an orbital eccentricity >0.5 and whose radial velocity (RV) data contain a trend in the residuals to the Keplerian orbit fit. These observations rule out stellar companions 4-8 mag fainter than the host star at passbands of 692 nm and 880 nm. The resolution and field of view of the instrument result in exclusion radii of 0.''05-1.''4, which excludes stellar companions within several AU of the host star in most cases. We further provide new RVs for the HD 4203 system that confirm that the linear trend previously observed in the residuals is due to an additional planet. Thesemore » results place dynamical constraints on the source of the planet's eccentricities, place constraints on additional planetary companions, and inform the known distribution of multiplicity amongst exoplanet host stars.« less
Authors:
;  [1] ;  [2] ;  [3] ; ;  [4] ;  [5] ;  [6] ;  [7]
  1. Department of Physics and Astronomy, San Francisco State University, 1600 Holloway Avenue, San Francisco, CA 94132 (United States)
  2. NASA Ames Research Center, Moffett Field, CA 94035 (United States)
  3. Department of Physics, Southern Connecticut State University, New Haven, CT 06515 (United States)
  4. Department of Astronomy and Astrophysics, Pennsylvania State University, 525 Davey Laboratory, University Park, PA 16802 (United States)
  5. NASA Exoplanet Science Institute, Caltech, MS 100-22, 770 South Wilson Avenue, Pasadena, CA 91125 (United States)
  6. National Optical Astronomy Observatory, 950 N. Cherry Ave, Tucson, AZ 85719 (United States)
  7. Institute for Astronomy, University of Hawaii, Honolulu, HI 96822 (United States)
Publication Date:
OSTI Identifier:
22357126
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 785; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ANGULAR MOMENTUM; DISTRIBUTION; LIMITING VALUES; MULTIPLICITY; ORBITS; PLANETS; RADIAL VELOCITY; RESOLUTION; STARS; TELESCOPES