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Published August 2000 | Accepted Version + Published
Journal Article Open

Discovery of a Bright Field Methane (T-Type) Brown Dwarf by 2MASS


We report the discovery of a bright (J = 13.83 ± 0.03) methane brown dwarf, or T dwarf, by the Two Micron All Sky Survey. This object, 2MASSI J0559191-140448, is the first brown dwarf identified by the newly commissioned CorMASS instrument mounted on the Palomar 60 inch (1.5 m) telescope. Near-infrared spectra from 0.9 to 2.35 μm show characteristic CH_4 bands at 1.1, 1.3, 1.6, and 2.2 μm, which are significantly shallower than those seen in other T dwarfs discovered to date. Coupled with the detection of an FeH band at 0.9896 μm and two sets of K I doublets at J band, we propose that 2MASS J0559-14 is a warm T dwarf, close to the transition between L and T spectral classes. The brightness of this object makes it a good candidate for detailed investigation over a broad wavelength regime and at higher resolution.

Additional Information

© 2000 American Astronomical Society. Received 2000 March 27; accepted 2000 April 17. We thank M. Strauss for the kind use of the SDSS 1624+00 near-infrared spectrum and acknowledge useful discussions with C. Griffith and M. Marley. We thank our anonymous referee for helpful comments and suggestions. We also recognize the efforts of the 2MASS staff and scientists in creating a truly incredible astronomical resource, and the expert assistance of the Palomar Observatory staff during imaging and spectroscopic observations. A. J. B., J. D. K., and J. E. G. acknowledge the support of the Jet Propulsion Laboratory, California Institute of Technology, which is operated under contract with the National Aeronautics and Space Administration. J. C. W. acknowledges support by NASA grant NAG 5-4376. Observations from Palomar Observatory were made as part of a continuing collaboration between the California Institute of Technology and Cornell University. The Digitized Sky Survey was produced at the Space Telescope Science Institute under grant NAG W-2166. SERC-EJ data were scanned by DSS from photographic data obtained using the UK Schmidt Telescope, operated by the Royal Observatory Edinburgh, with funding from the UK Science and Engineering Research Council. DSS images were obtained from the Canadian Astronomy Data Centre, which is operated by the Herzberg Institute of Astrophysics, National Research Council of Canada. IRAF is distributed by the National Optical Astronomy Observatories, which are operated by the Association of Universities for Research in Astronomy, Inc., under cooperative agreement with the National Science Foundation. This publication makes use of data from the Two Micron All Sky Survey, which is a joint project of the University of Massachusetts and the Infrared Processing and Analysis Center, funded by the National Aeronautics and Space Administration and the National Science Foundation.

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August 21, 2023
October 19, 2023