Pre-discovery imaging of the 2 pc brown dwarf binary WISE 1049-5319

luhman-centered-on-wise-possii-red

WISE 1049-5319 is the brown dwarf binary recently discovered at a distance of only 2.0 ± 0.15 pc by Luhman (2013, now published). The above image spans 10 x 10 arcminutes and is centered on the WISE position. This is the POSS-II red imaging of the region provided by the Digitized Sky Survey, obtained in 1992. The lines indicate the detection of the brown dwarf pair in this imaging, as identified in the paper (arXiv.org pdf preprint, Fig. 1, p. 6), to which readers should compare. The red band magnitude is ~ 18.6. The box is the current position, again from inspection of the published imaging. The proper motion is roughly 3 arcseconds per year, so the object has moved approximately one arcminute in the ~ 20 years since the POSS imaging, as can be seen.

Further discussion of this object has been published today by Mamajek (arXiv pdf) who detects it in images from 1984, which also hint at its binarity. The object can be detected on the DSS IR plate from 1978, as Luhman indicates. This is the first object outside the solar system to be found so close to the Sun since the 1916 measurement of Barnard’s Star, for which the accepted distance is 1.834 ± 0.001 pc. That it has been overlooked for so long is a consequence of its location close to the galactic plane, which previous searches have largely avoided because of the difficulties of identifying faint, nearby, moving objects against the dense background star fields.

Update: Seventy-six T dwarfs from the UKIDSS Large Area Survey

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One Response to “Pre-discovery imaging of the 2 pc brown dwarf binary WISE 1049-5319”

  1. […] that the point spread function of the WISE data is not as narrow as the near-infrared (1999) or red visible (1992) data, as would be expected with imaging in the thermal infrared, but with accurate […]

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