منابع مشابه
Infrared Parallaxes for Methane T Dwarfs
We report final results from our 2.5 year infrared parallax program carried out with the European Southern Observatory 3.5m New Technology Telescope and the SOFI infrared camera. Our program targeted precision astrometric observations of ten T type brown dwarfs in the J band. Full astrometric solutions (including trigonometric parallaxes) for nine T dwarfs are provided along with proper motion ...
متن کاملParallaxes of L and T dwarfs
We discuss a new program to measure the parallaxes of a number of L and T dwarfs, objects that bridge the gap between M dwarfs and planets. This pilot project tests the feasibility of using large telescopes with infrared detectors to determine parallaxes at the level of milli-arcseconds (mas). First results show that we are able to achieve the required centroiding precision and simulations indi...
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We present the first mid-infrared spectra of two cool white dwarfs obtained with the Spitzer Space Telescope. We also present 3:5Y8 m photometry for 19 cool white dwarfs with 5000 K TeA 9000 K. We perform a detailed model atmosphere analysis of these white dwarfs by fitting their UBVRIJHK and Spitzer photometry with state-ofthe-art model atmospheres, and demonstrate that the optical and infrare...
متن کاملA Unified Near-infrared Spectral Classification Scheme for T Dwarfs
A revised near-infrared classification scheme for T dwarfs is presented, based on and superseding prior schemes developed by Burgasser and coworkers and Geballe and coworkers, and defined following the precepts of the MK process. Drawing from two large spectroscopic libraries of T dwarfs identified largely in the SloanDigital Sky Survey and the Two Micron All Sky Survey, nine primary spectral s...
متن کاملParallaxes of five L Dwarfs with a Robotic Telescope
We report the parallax and proper motion of five L dwarfs obtained with observations from the robotic Liverpool Telescope. Our derived proper motions are consistent with published values and have considerably smaller errors. Based on our spectral type versus absolute magnitude diagram, we do not find any evidence for binaries among our sample, or, at least no comparable mass binaries. Their spa...
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ژورنال
عنوان ژورنال: Symposium - International Astronomical Union
سال: 2003
ISSN: 0074-1809
DOI: 10.1017/s0074180900211005