AAS 201st Meeting, January, 2003
Session 33. Stars Dead or Alive
Oral, Monday, January 6, 2003, 2:00-3:30pm, 606-607

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[33.05] Preliminary USNO Infrared Parallax Results for L- and T-Dwarfs

F.J. Vrba (U.S. Naval Observatory), A.A. Henden (USRA/U.S. Naval Observatory), C.B. Luginbuhl, H.H. Guetter (U.S. Naval Observatory)

In September 2000 we initiated a near-infrared parallax and proper motion program aimed at L- and T-dwarfs as a complement to the USNO CCD optical program. The near-infrared program employs a reflective optics imager (ASTROCAM) on the Strand 1.55-m Astrometric Reflector using a 1024x1024 ALADDIN InSb array providing a 6.2 x 6.2 arcmin FOV.The initial program consists of 41 stars selected from the SDSS (19 stars) and 2MASS (22 stars) surveys, many of which were provided to us prior to public release via our collaboration in these surveys. The distribution of spectral types for these stars are L0-L4 5 stars, L5-L8 17 stars, T0-T4 7 stars, T4-T8 12 stars. Seven stars are in common with the USNO CCD program to provide an independent verification of the astrometric results. As of this writing, stars on the near-infrared program have been observed over a time interval of from 1.2 to 2.0 years with an average of 22 nights of independent data for each star. These data are of sufficient quality, number, and time span to allow us to provide preliminary parallax and proper motion results.

The author(s) of this abstract have provided an email address for comments about the abstract: fjv@nofs.navy.mil

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Bulletin of the American Astronomical Society, 34, #4
© 2002. The American Astronomical Soceity.