Results 21 to 30 of about 6,740 (303)
Infrared Parallaxes for Methane T Dwarfs [PDF]
The Astronomical Journal, 2003 submitted to The Astronomical ...
Tinney, C. G. +2 more
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Clouds, Brightening and Multiplicity Across the L Dwarf∕T Dwarf Transition [PDF]
AIP Conference Proceedings, 2009 The transition between the two lowest-luminosity spectral classes of brown dwarfs--the L dwarfs and T dwarfs--is traversed by nearly all brown dwarfs as they cool over time. Yet distinct features of this transition, such as the "J-band bump" and an unusually high rate of multiplicity, remain outstanding problems, although evidence points to condensate ...
Adam J. Burgasser, Eric Stempels
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Methane and the Spectra of T Dwarfs [PDF]
Symposium - International Astronomical Union, 2003 We have updated our PHOENIX model atmospheres and theoretical spectra for ultracool dwarfs with new opacity data for methane based on line strength predictions with the STDS software. By extending the line list to rotational levels of J = 40 we can significantly improve the shape of the near-IR absorption features of CH4, and in addition find an ...
Homeier, Derek +2 more
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First T dwarfs in the VISTA Hemisphere Survey [PDF]
Astronomy & Astrophysics, 2012 The aim of the project is to improve our current knowledge of the density of T dwarfs and the shape of the substellar initial mass function by identifying a magnitude-limited sample of T dwarfs in the full southern sky. We present the results of a photometric search aimed at discovering cool brown dwarfs in the Southern sky imaged at infrared ...
Lodieu, N +23 more
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Retrieval Study of Brown Dwarfs Across the L-T Sequence
, 2022 A large suite of 228 atmospheric retrievals is performed on a curated sample of 19 brown dwarfs spanning the L0 to T8 spectral types using the open-source Helios-r2 retrieval code, which implements the method of short characteristics for radiative ...
Kitzmann, Daniel +4 more
core +1 more source
Parallaxes of L and T dwarfs [PDF]
Proceedings of the International Astronomical Union, 2004 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
R. L. Smart +2 more
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T Dwarf Photometric Variability [PDF]
Symposium - International Astronomical Union, 2003 We report on a J and H photometric variability survey of 10 T dwarfs. Four brown dwarfs in the sample show significant J band variability at the 99% confidence level or higher. The amplitude of variation ranges from 2 to 17%. Our data show evidence of variability for late as well as early T dwarfs.
Etienne Artigau +2 more
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Modeling Brown Dwarfs, L Dwarfs, and T Dwarfs [PDF]
Symposium - International Astronomical Union, 2003 In this contribution, I review a subset of our recent efforts in spectral and opacity modeling aimed at guiding the study of brown dwarfs, L dwarfs, and T dwarfs. I discuss theoretical calculations of the alkali line profiles, newly generated CrH opacities, new evidence for refractory rainout in T dwarfs from optical spectral measurements, and the ...
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The 2MASS Wide-Field T Dwarf Search. III. Seven New T Dwarfs and Other Cool Dwarf Discoveries [PDF]
The Astronomical Journal, 2004 27 pages incl. 9 figures and 8 tables, accepted for publication AJ, May 2004; note that findercharts are provided separately as jpg ...
Burgasser, Adam J. +5 more
openaire +2 more sources
DA white dwarfs in Sloan Digital Sky Survey Data Release 7 and a search for infrared excess emission [PDF]
, 2011 We present a method which uses colour–colour cuts on the Sloan Digital Sky Survey (SDSS) photometry to select white dwarfs with hydrogen-rich (DA) atmospheres without the recourse to spectroscopy.
Farihi, J. +19 more
core +1 more source