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Title: Characterization of the benchmark binary NLTT 33370 {sup ,}

We confirm the binary nature of the nearby, very low mass (VLM) system NLTT 33370 with adaptive optics imaging and present resolved near-infrared photometry and integrated light optical and near-infrared spectroscopy to characterize the system. VLT-NaCo and LBTI-LMIRCam images show significant orbital motion between 2013 February and 2013 April. Optical spectra reveal weak, gravity-sensitive alkali lines and strong lithium 6708 Å absorption that indicate the system is younger than field age. VLT-SINFONI near-IR spectra also show weak, gravity-sensitive features and spectral morphology that is consistent with other young VLM dwarfs. We combine the constraints from all age diagnostics to estimate a system age of ∼30-200 Myr. The 1.2-4.7 μm spectral energy distribution of the components point toward T {sub eff} = 3200 ± 500 K and T {sub eff} = 3100 ± 500 K for NLTT 33370 A and B, respectively. The observed spectra, derived temperatures, and estimated age combine to constrain the component spectral types to the range M6-M8. Evolutionary models predict masses of 97{sub −48}{sup +41} M{sub Jup} and 91{sub −44}{sup +41} M{sub Jup} from the estimated luminosities of the components. KPNO-Phoenix spectra allow us to estimate the systemic radial velocity of the binary. The Galactic kinematics ofmore » NLTT 33370AB are broadly consistent with other young stars in the solar neighborhood. However, definitive membership in a young, kinematic group cannot be assigned at this time and further follow-up observations are necessary to fully constrain the system's kinematics. The proximity, age, and late-spectral type of this binary make it very novel and an ideal target for rapid, complete orbit determination. The system is one of only a few model calibration benchmarks at young ages and VLMs.« less
Authors:
; ; ; ; ; ;  [1] ; ;  [2] ;  [3] ; ; ; ;  [4] ; ;  [5] ;  [6] ;  [7] ;  [8]
  1. Max-Planck-Institut für Astronomie, Königstuhl 17, D-69117 Heidelberg (Germany)
  2. Department of Astrophysics, Division of Physical Sciences, American Museum of Natural History, Central Park West at 79th Street, New York, NY 10024 (United States)
  3. Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)
  4. Steward Observatory, Department of Astronomy, University of Arizona, 933 N. Cherry Ave, Tucson, AZ 85721 (United States)
  5. UJF-Grenoble 1/CNRS-INSU, Institut de Planètologie et d'Astrophysique de Grenoble (IPAG) UMR 5274, Grenoble F-38041 (France)
  6. European Southern Observatory, Casilla 19001, Santiago 19 (Chile)
  7. LESIA, Observatoire de Paris, CNRS, University Pierre et Marie Curie Paris 6 and University Denis Diderot Paris 7, 5 place Jules Janssen, F-92195 Meudon (France)
  8. Department of Astronomy, University of Virginia, Charlottesville, VA 22904 (United States)
Publication Date:
OSTI Identifier:
22351368
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 783; 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; ABSORPTION; ABSORPTION SPECTROSCOPY; BENCHMARKS; CALIBRATION; ENERGY SPECTRA; GRAVITATION; IMAGES; INFRARED SPECTRA; LIMITING VALUES; LUMINOSITY; MASS; OPTICS; PHOTOMETRY; RADIAL VELOCITY; STARS; VISIBLE RADIATION