Toward Spectral Classification of L and T Dwarfs: Infrared and Optical Spectroscopy and Analysis

@article{Geballe2001TowardSC,
  title={Toward Spectral Classification of L and T Dwarfs: Infrared and Optical Spectroscopy and Analysis},
  author={Thomas R. Geballe and Gillian R. Knapp and Sandy K. Leggett and X. L. Fan and David A. Golimowski and Scott Anderson and Jonathan Brinkmann and Istv{\'a}n Csabai and James E. Gunn and Suzanne L. Hawley and Gregory S. Hennessy and Todd J. Henry and G. J. Hill and Robert B. Hindsley and Željko Ivezi{\'c} and Robert H. Lupton and A. McDaniel and Jeffrey A. Munn and Vijay K. Narayanan and Eric W. Peng and J. R. Pier and Constance M. Rockosi and Donald P. Schneider and J. Allyn Smith and Michael A. Strauss and Zlatan I. Tsvetanov and Alan K. Uomoto and Donald G. York and Wei Zheng},
  journal={The Astrophysical Journal},
  year={2001},
  volume={564},
  pages={466 - 481}
}
We present 0.6-2.5 μm, R ≳ 400 spectra of 27 cool, low-luminosity stars and substellar objects. Based on these and previously published spectra, we develop a preliminary spectral classification system for L and T dwarfs. For late L and T types the classification system is based entirely on four spectral indices in the 1-2.5 μm interval. Two of these indices are derived from water absorption bands at 1.15 and 1.4 μm, the latter of which shows a smooth increase in depth through the L and T… 

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References

SHOWING 1-10 OF 64 REFERENCES

The Spectra of T Dwarfs. I. Near-Infrared Data and Spectral Classification

We present near-infrared spectra for a sample of T dwarfs, including 11 new discoveries made using the 2 Micron All Sky Survey. These objects are distinguished from warmer (L-type) brown dwarfs by

The Classification of T Dwarfs

We discuss methods for classifying T dwarfs based on spectral morphological features and indices. T dwarfs are brown dwarfs which exhibit methane absorption bands at 1.6 and 2.2 μm. Spectra at red

Infrared Spectra and Spectral Energy Distributions of Late M and L Dwarfs

We have obtained 1.0-2.5 μm spectra at R ~ 600 of 14 disk dwarfs with spectral types M6-L7. For four of the dwarfs, we have also obtained infrared spectra at R ~ 3000 in several narrow intervals. In

Spectroscopic Classification of Late-M and L Field Dwarfs

We present spectra for 12 new ultracool dwarfs found in the DENIS infrared survey. Seven of them have spectral types at the bottom of the M-class (M8–M9.5), and the other five belong to the cooler

Near-Infrared Spectral Classification of Late M and L Dwarfs

We present near-infrared (1–2.5 μm), low-resolution spectroscopy of 11 ultracool dwarfs, with spectral types ranging from M7 to L8. Combining our observations with data published by Leggett et al. in

Infrared Spectroscopy of Brown Dwarfs: the Onset of CH 4 Absorption in L Dwarfs and the L/T Transition

We present infrared spectra of brown dwarfs with spectral types from mid L to T. The 0.9–2.5 μm spectra of three dwarfs found by the Sloan Digital Sky Survey contain absorption bands of both methane

Infrared Photometry of Late-M, L, and T Dwarfs

We present ZJHKL′M′ photometry of a sample of 58 late M, L, and T dwarfs, most of which are identified from the Sloan Digital Sky Survey and the Two Micron All-Sky Survey. Near-infrared spectra and

NICS-TNG Low-Resolution 0.85-2.45 micron Spectra of L Dwarfs: A Near-Infrared Spectral Classification Scheme for Faint Dwarfs

We present complete near-infrared (0.85-2.45 μm), low-resolution (~100) spectra of a sample of 26 disk L dwarfs with reliable optical spectral type classification. The observations have been obtained

K-Band Spectra and Narrowband Photometry of DENIS Field Brown Dwarfs

Infrared spectra at 1.9–2.5 μm and narrowband photometry of three low-mass objects, DENIS-P J0205.4-1159, J1058.7-1548, and J1228.2-1547, are presented. As shown previously by Delfosse et al.,

Dwarfs Cooler than “M”: The Definition of Spectral Type “L” Using Discoveries from the 2-Micron All-Sky Survey (2MASS)

Before the 2-Micron All-Sky Survey (2MASS) began, only six objects were known with spectral types later than M9.5 V. In the first 371 deg2 of actual 2MASS survey data, we have identified another 20
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