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Ultracool Objects: L, T, and Y Dwarfs

  • Michael C. Cushing
Chapter
Part of the Astrophysics and Space Science Library book series (ASSL, volume 401)

Abstract

The discovery of the first bona fide brown dwarfs in 1995 ushered in a new era in both stellar and planetary astrophysics. The emergent spectra of brown dwarfs are distinct from those of the lowest-mass stars and thus the creation of three new spectral classes, L, T, and Y, were required in order to classify them. In this chapter, I provide a historical review of the creation of these spectral classes and briefly discuss the physical conditions that give rise to the variations in spectral morphology used for classification.

Keywords

Spectral Index Spectral Sequence Effective Temperature Spectral Type Vanadium Oxide 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Notes

Acknowledgements

I would like to thank Morag Hastie and J. Davy Kirkpatrick for providing useful comments on early versions of the manuscript and J. Davy Kirkpatrick and Adam Burgasser for ensuring the accuracy of the early history of the L and T dwarfs. The spectra shown in Figs. 24 were kindly provided by J. Davy Kirkpatrick, Adam Burgasser, and Sandy Leggett. This paper has benefitted from the SpeX Prism Spectral Libraries, maintained by Adam Burgasser at http://pono.ucsd.edu/~adam/browndwarfs/spexprism, and has made use of the NASA/ IPAC Infrared Science Archive, which is operated by the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration. Finally I also would like to thank Viki Joergens for organizing the thoroughly enjoyable conference 50 Years of Brown Dwarfs: from Theoretical Prediction to Astrophysical Studies held at Ringberg Castle, Bavaria, Germany in October 2012.

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© Springer International Publishing Switzerland 2014

Authors and Affiliations

  1. 1.Department of Physics and AstronomyUniversity of ToledoToledoUSA

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