Precise estimation of fundamental parameters (e.g., Teff , log g and [Fe/H]) for cool giants is a long-standing and challenging problem in astronomy. The estimation of these parameters is very important to understand and classify stellar populations in different Galactic and extragalactic environments. Spectroscopic studies of cool giants in optical and near-infrared (NIR) help us to derive their fundamental parameters precisely. TIFR Near Infrared Spectrometer and Imager (TIRSPEC) on 2-m Himalayan Chandra Telescope and TIFR-ARIES Near Infrared Spectrometer (TANSPEC) on 3.6-m Devasthal Optical Telescope (DOT) are very useful to characterise cool giants at different Galactic locations.
The first part of my presentation will focus on the calibration and science observations of TANSPEC instrument in the low-resolution prism mode and its potential use in long-term survey programs. I will also talk about the successful installation of TIFR Near Infrared Imaging Camera-II (TIRCAM2) at the side port of the DOT and will present exciting preliminary results.
In the second part of my presentation, I shall present our established quantitative diagnostic tools to characterise cool giants precisely from low-resolution near-infrared spectra using the archival data. We study the behaviour of spectral features with fundamental parameters using the low-resolution spectra so-that we can extend our work in more detail using TIRSPEC and TANSPEC instruments. With the TANSPEC instrument and its’ simultaneous coverage in optical and NIR wavelength, a comparative study between different spectral indices in optical and NIR regime would be very helpful in the characterisation
of cool stars.