Constraints on the binary Properties of mid to late T dwarfs from Hubble Space Telescope WFC3 Observations

Abstract

We used HST/WFC3 observations of a sample of 26 nearby ($\le$20 pc) mid to late T dwarfs to search for cooler companions and measure the multiplicity statistics of brown dwarfs. Tightly-separated companions were searched for using a double-PSF fitting algorithm. We also compared our detection limits based on simulations to other prior T5+ brown dwarf 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 of T-type brown dwarfs. Modeling selection effects and adopting previously derived separation and mass ratio distributions, we find an upper limit total binary fraction 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.

References in corpus (23)

• The UKIRT Infrared Deep Sky Survey (UKIDSS)
• The properties of brown dwarfs and low-mass hydrogen-burning stars formed by disc fragmentation
• Young L Dwarfs Identified in the Field: A Preliminary Low-Gravity, Optical Spectral Sequence from L0 to L5
• Meeting the Cool Neighbors. IX. The Luminosity Function of M7-L8 Ultracool Dwarfs in the Field
• Chromospheric Activity, Rotation, and Rotational Braking in M and L Dwarfs
• Discovery of Two T Dwarf Companions with the Spitzer Space Telescope
• A Sample of Very Young Field L Dwarfs and Implications for the Brown Dwarf "Lithium Test" at Early Ages
• Hubble Space Telescope NICMOS Observations of T Dwarfs: Brown Dwarf Multiplicity and New Probes of the L/T Transition
• Activity and Kinematics of Ultracool Dwarfs Including An Amazing Flare Observation
• Discovery of 11 New T Dwarfs in the Two Micron All-Sky Survey, Including a Possible L/T Transition Binary
• A very cool brown dwarf in UKIDSS DR1
• Exploring the substellar temperature regime down to ~550K
• Keck Laser Guide Star Adaptive Optics Monitoring of 2MASS J1534-2952AB: First Dynamical Mass Determination of a Binary T Dwarf
• HD3651B: the first directly imaged brown dwarf companion of an exoplanet host star
• Discovery of a T Dwarf Binary with the Largest Known J-Band Flux Reversal
• Discovery of new nearby L and late-M dwarfs at low Galactic latitude from the DENIS database
• Finding ultracool brown dwarfs with MegaCam on CFHT: method and first results
• Discovery of a High Proper Motion L Dwarf Binary: 2MASS J15200224-4422419AB
• Three New Cool Brown Dwarfs Discovered with the Wide-field Infrared Survey Explorer (WISE) and an Improved Spectrum of the Y0 Dwarf WISE J041022.71+150248.4
• New, nearby bright southern ultracool dwarfs
• Discovery of a nearby L-T transition object in the Southern Galactic plane
• Discovery of a 66 mas Ultracool Binary with Laser Guide Star Adaptive Optics
• Two T dwarfs from the UKIDSS Early Data Release

Cited by in corpus (14)

• The Field Substellar Mass Function Based on the Full-sky 20-pc Census of 525 L, T, and Y Dwarfs
• Photometry and Proper Motions of M, L, and T Dwarfs from the Pan-STARRS1 3$\pi$ Survey
• Uniform Atmospheric Retrieval Analysis of Ultracool Dwarfs II: Properties of 11 T-dwarfs
• Constraining the multiplicity statistics of the coolest brown dwarfs: binary fraction continues to decrease with spectral type
• The Ultracool SpeXtroscopic Survey. I. Volume-Limited Spectroscopic Sample and Luminosity Function of M7$-$L5 Ultracool Dwarfs
• Uniform Forward-Modeling Analysis of Ultracool Dwarfs. II. Atmospheric Properties of 55 Late-T Dwarfs
• The Surface Densities of Disk Brown Dwarfs in JWST Surveys
• Searching for Binary Y dwarfs with the Gemini Multi-Conjugate Adaptive Optics System (GeMS)
• Characterizing the Atmospheres of the HR8799 Planets with HST/WFC3
• On the Binary Frequency of the Lowest Mass Members of the Pleiades with Hubble Space Telescope Wide Field Camera 3
• CWISE J014611.20-050850.0AB: The Widest Known Brown Dwarf Binary in the Field
• A Search for Substellar Companions to the Two Nearest Brown Dwarf Systems
• NICMOS Kernel-Phase Interferometry II: Demographics of Nearby Brown Dwarfs
• WISE J061213.85-303612.5: a new T-dwarf binary candidate