NICS-TNG low-resolution 0.85-2.45um spectra of L-Dwarfs: a near-infrared spectral classification scheme for faint dwarfs
L. Testi (1), F. D'Antona (2), F. Ghinassi (3), et al.
(1) Osservatorio Astrofisico di Arcetri,
Largo Enrico Fermi 5, I-50125 Firenze, Italy
(2) Osservatorio Astronomico di Roma, Frascati, Italy
(3) Centro Galileo Galilei and Telescopio Nazionale Galileo
We present complete near-infrared (0.85-2.45 um), low-resolution
(~100) spectra of a sample of 26 disk L-dwarfs with reliable
optical spectral type classification. The observations have been
obtained with NICS at the TNG using a prism-based optical element
(the Amici device)
that provides a complete spectrum of the source on the detector.
Our observations show that
low-resolution near-infrared spectroscopy can be used to determine
the spectral classification of L-dwarfs in a fast but accurate way.
We present a library of spectra that can be used as templates for
spectral classification of faint dwarfs. We also discuss
a set of near-infrared spectral indices well correlated
with the optical spectral types that can be used to accurately classify
L-dwarfs earlier than L6.