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Title: The trends high-contrast imaging survey. IV. The occurrence rate of giant planets around M dwarfs

Doppler-based planet surveys have discovered numerous giant planets but are incomplete beyond several AU. At larger star-planet separations, direct planet detection through high-contrast imaging has proven successful, but this technique is sensitive only to young planets and characterization relies upon theoretical evolution models. Here we demonstrate that radial velocity measurements and high-contrast imaging can be combined to overcome these issues. The presence of widely separated companions can be deduced by identifying an acceleration (long-term trend) in the radial velocity of a star. By obtaining high spatial resolution follow-up imaging observations, we rule out scenarios in which such accelerations are caused by stellar binary companions with high statistical confidence. We report results from an analysis of Doppler measurements of a sample of 111 M-dwarf stars with a median of 29 radial velocity observations over a median time baseline of 11.8 yr. By targeting stars that exhibit a radial velocity acceleration ({sup t}rend{sup )} with adaptive optics imaging, we determine that 6.5% ± 3.0% of M-dwarf stars host one or more massive companions with 1 < m/M{sub J} < 13 and 0 < a < 20 AU. These results are lower than analyses of the planet occurrence rate around higher-mass stars. Wemore » find the giant planet occurrence rate is described by a double power law in stellar mass M and metallicity F ≡ [Fe/H] such that f(M,F)=0.039{sub −0.028}{sup +0.056}M{sup 0.8{sub −}{sub 0}{sub .}{sub 9}{sup +{sup 1{sup .{sup 1}}}}}10{sup (3.8±1.2)F}. Our results are consistent with gravitational microlensing measurements of the planet occurrence rate; this study represents the first model-independent comparison with microlensing observations.« less
Authors:
 [1] ;  [2] ;  [3] ;  [4] ;  [5]
  1. Cahill Center for Astronomy and Astrophysics, California Institute of Technology, 1200 East California Boulevard, MC 249-17, Pasadena, CA 91125 (United States)
  2. Department of Physics, University of Notre Dame, 225 Nieuwland Science Hall, Notre Dame, IN 46656 (United States)
  3. Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)
  4. Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI 96822 (United States)
  5. B-20 Hearst Field Annex, Astronomy Department, University of California, Berkeley, Berkeley, CA 94720 (United States)
Publication Date:
OSTI Identifier:
22348176
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 781; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ACCELERATION; COMPARATIVE EVALUATIONS; DETECTION; DWARF STARS; EVOLUTION; MASS; METALLICITY; PLANETS; RADIAL VELOCITY; SATELLITES; SPATIAL RESOLUTION