Effective temperatures from IGRINS high-res. sp.

Fortunately, high-resolution infrared spectroscopy is a powerful tool for determining the temperatures of stars with no dependence on interstellar extinction. It has long been known that the depth ratios of temperature-sensitive and relatively insensitive spectral lines are excellent temperature indices.

In this work, we provide the first extensive line depth ratio (LDR) method application in the infrared region that encompasses both the H and K bands (1.48{mu}m-2.48{mu}m). We applied the LDR method to high-resolution (R~45000) H- and K-band spectra of 110 stars obtained with the Immersion Grating Infrared Spectrograph. Our sample contained stars with 3200<Teff(K)<5500, 0.20<=logg<4.6, and -1.5<[M/H]<0.5.