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Title: MID-INFRARED HIGH-CONTRAST IMAGING OF HD 114174 B: AN APPARENT AGE DISCREPANCY IN A ''SIRIUS-LIKE'' BINARY SYSTEM

We present new observations of the faint ''Sirius-like'' companion discovered to orbit HD 114174. Previous attempts to image HD 114174 B at mid-infrared wavelengths using NIRC2 at Keck have resulted in a non-detection. Our new L'-band observations taken with the Large Binocular Telescope and L/M-band InfraRed Camera recover the companion (ΔL = 10.15 ± 0.15 mag, ρ = 0.''675 ± 0.''016) with a high signal-to-noise ratio (10σ). This measurement represents the deepest L' high-contrast imaging detection at subarcsecond separations to date, including extrasolar planets. We confirm that HD 114174 B has near-infrared colors consistent with the interpretation of a cool white dwarf (WD; J – L' = 0.76 ± 0.19 mag, K – L' = 0.64 ± 0.20). New model fits to the object's spectral energy distribution indicate a temperature T {sub eff} = 4260 ± 360 K, surface gravity log g = 7.94 ± 0.03, a cooling age t{sub c} ≈ 7.8 Gyr, and mass M = 0.54 ± 0.01 M {sub ☉}. We find that the cooling ages given by theoretical atmospheric models do not agree with the age of HD 114174 A derived from both isochronological and gyrochronological analyses. We speculate on possible scenarios to explain the apparent age discrepancy betweenmore » the primary and secondary. HD 114174 B is a nearby benchmark WD that will ultimately enable a dynamical mass estimate through continued Doppler and astrometric monitoring. Efforts to characterize its physical properties in detail will test theoretical atmospheric models and improve our understanding of WD evolution, cooling, and progenitor masses.« less
Authors:
;  [1] ; ; ; ; ;  [2] ; ;  [3] ;  [4] ; ;  [5]
  1. Department of Physics, University of Notre Dame, 225 Nieuwland Science Hall, Notre Dame, IN 46556 (United States)
  2. Department of Astronomy, University of Arizona, 993 N. Cherry Ave, Tucson, AZ 85721 (United States)
  3. Department of Physics and Astronomy, University of Oklahoma, Norman, OK 73019 (United States)
  4. Department of Astronomy, University of Virginia, Charlottesville, VA 22904 (United States)
  5. Istituto Nazionale di Astrofisica, Osservatorio Astrofisico di Arcetri Largo E. Fermi I-550125 Firenze (Italy)
Publication Date:
OSTI Identifier:
22365986
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal Letters; Journal Volume: 783; 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; BENCHMARKS; BINARY STARS; CAMERAS; COLOR; DETECTION; ENERGY SPECTRA; GRAVITATION; INTERMEDIATE INFRARED RADIATION; MASS; OPTICS; ORBITS; SIGNAL-TO-NOISE RATIO; STAR EVOLUTION; TELESCOPES; WHITE DWARF STARS