SpeX: 0.7-5.3 Micron Medium-Resolution Spectrograph and Imager
NASA InfraRed Telescope Facility(IRTF), Institute for Astronomy, University of Hawaii

IRTF Extended Spectral Library


The IRTF Extended Spectral Library is a collection of 0.7-2.5 μm mostly stellar spectra observed at a resolving power of R ≡ λ/Δλ ~ 2000 with the medium-resolution spectrograph, SpeX, at the NASA Infrared Telescope Facility (IRTF) on Mauna Kea. The current release expands the metallicity coverage of the original IRTF Spectral Library (Rayner et al. 2009) from mainly solar metallicity to -1.7 < [Fe/H] < 0.3. The current release is mainly for late-type stars. The average S/N for the stellar library spectra are ~100, the spectral continuum shape is preserved, and the spectra were absolutely flux calibrated using the Two Micron All Sky Survey (2MASS) photometry.

Features of the library include:

  • A spectral range of 0.7 to 2.5 μm (with a subset from 0.8 to 5.2 μm)

  • S/N ~ 100 at λ < 4 μm

  • Spectral continuum shape is preserved

  • Absolutely flux calibrated using Two Micron All Sky Survey (2MASS) photometry.