We present here medium resolution ({lambda}/{Delta}{lambda}~1200) H- and K-band spectra of M-type dwarf stars covering the wavelength ranges 1.50-1.80{mu}m and 1.95-2.45{mu}m. The sample includes 53 dwarf stars (M0V-M7V) from new observations using the TIFR Near-Infrared Spectrometer and Imager instrument on the 2-m Himalayan Chandra Telescope. Using interferometrically measured effective temperature (T_eff_), radius and luminosity of nearby bright calibrator stars, we have created new empirical relationships among those fundamental parameters and spectral indices. The equivalent widths of H-band spectral features like Mg (1.57{mu}m), Al (1.67{mu}m) and Mg (1.71{mu}m), and the H_2_O-H index are found to be good indicators of T_eff_, radius and luminosity and we establish linear functions using these features relating to those stellar parameters. The root-mean-squared error of our best fits are 102K, 0.027R_{sun} and 0.12dex respectively. Using spectral-type standards along with known parallaxes, we calibrate both H- and K-band H_2_O indices as a tracer of spectral type and absolute K_s magnitude. Metallicities of M-dwarf samples are estimated using the K-band calibration relationships. The masses of M dwarfs could be determined using the luminosity (L/L_{sun}_) and we establish a new empirical relation for this. We also compare and contrast our results with other similar work from the literature.

Cone search capability for table J/MNRAS/493/4533/table1 (Log of H- and K-band spectroscopic observations using 2-m HCT and observational properties of M dwarfs)