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Title: DISCOVERY OF THE Y1 DWARF WISE J064723.23–623235.5

We present the discovery of a very cold, very low mass, nearby brown dwarf using data from the NASA Wide-field Infrared Survey Explorer (WISE). The object, WISE J064723.23–623235.5, has a very red WISE color of W1–W2 > 3.77 mag and a very red Spitzer Space Telescope color of ch1–ch2 = 2.82 ± 0.09 mag. In J{sub MKO} –ch2 color (7.58 ± 0.27 mag) it is one of the two or three reddest brown dwarfs known. Our grism spectrum from the Hubble Space Telescope (HST) confirms it to be the seventeenth Y dwarf discovered, and its spectral type of Y1 ± 0.5 makes it one of the four latest-type Y dwarfs classified. Astrometric imaging from Spitzer and HST, combined with data from WISE, provides a preliminary parallax of π = 115 ± 12 mas (d = 8.7 ± 0.9 pc) and proper motion of μ = 387 ± 25 mas yr{sup –1} based on 2.5 yr of monitoring. The spectrum implies a blue J–H color, for which model atmosphere calculations suggest a relatively low surface gravity. The best fit to these models indicates an effective temperature of 350-400 K and a mass of ∼5-30 M{sub Jup}. Kinematic analysis hints that thismore » object may belong to the Columba moving group, which would support an age of ∼30 Myr and thus an even lower mass of <2 M{sub Jup}, but verification would require a radial velocity measurement not currently possible for a J = 22.7 mag brown dwarf.« less
Authors:
; ; ;  [1] ; ;  [2] ;  [3] ;  [4]
  1. Infrared Processing and Analysis Center, MS 100-22, California Institute of Technology, Pasadena, CA 91125 (United States)
  2. Department of Physics and Astronomy, MS 111, University of Toledo, 2801 West Bancroft Street, Toledo, OH 43606-3328 (United States)
  3. School of Physics, University of New South Wales, Sydney, NSW 2052 (Australia)
  4. Department of Astronomy, University of Chile, Camino El Observatorio 1515, Casilla 36-D Santiago (Chile)
Publication Date:
OSTI Identifier:
22270812
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 776; 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; ASTRONOMY; ASTROPHYSICS; COLOR; DWARF STARS; GRAVITATION; INFRARED SPECTRA; INFRARED SURVEYS; MASS; NASA; PROPER MOTION; RADIAL VELOCITY; TELESCOPES