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Title: Constraints on the binary properties of mid- to late T dwarfs from Hubble space telescope WFC3 observations

We used Hubble Space Telescope/Wide Field Camera 3 (WFC3) observations of a sample of 26 nearby (≤20 pc) mid- to late T dwarfs to search for cooler companions and measure the multiplicity statistics of brown dwarfs (BDs). Tightly separated companions were searched for using a double point-spread-function-fitting algorithm. We also compared our detection limits based on simulations to other prior T5+ BD binary programs. No new wide or tight companions were identified, which is consistent with the number of known T5+ binary systems and the resolution limits of WFC3. We use our results to add new constraints to the binary fraction (BF) of T-type BDs. Modeling selection effects and adopting previously derived separation and mass ratio distributions, we find an upper limit total BF of <16% and <25% assuming power law and flat mass ratio distributions, respectively, which are consistent with previous results. We also characterize a handful of targets around the L/T transition.
Authors:
;  [1] ;  [2] ;  [3] ;  [4] ;  [5] ;  [6]
  1. Centro de Astrobiología (INTA-CSIC), Departamento de Astrofísica, P.O. Box 78, E-28691 Villanueva de la Cañada, Madrid (Spain)
  2. Center for Astrophysics and Space Science, University of California San Diego, La Jolla, CA 92093 (United States)
  3. ESA–ESAC, Gaia SOC. P.O. Box 78, E-28691 Villanueva de la Cañada, Madrid (Spain)
  4. Centro de Astrobiología (INTA-CSIC), Departamento de Astrofísica. Carretera de Ajalvir km 4, E-28550 Torrejín de Ardoz, Madrid (Spain)
  5. Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States)
  6. Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI 96822 (United States)
Publication Date:
OSTI Identifier:
22342193
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; CAMERAS; COMPARATIVE EVALUATIONS; DISTRIBUTION; DWARF STARS; HEAT EXCHANGERS; LIMITING VALUES; MASS; MULTIPLICITY; RESOLUTION; SENSITIVITY; SIMULATION; SPACE; STARS; TELESCOPES