Preliminary results of TANSPEC calibration and precursor studies for a few possible TANSPEC science cases.

Near-Infrared astronomy provides great opportunities to probe cool stellar populations at different galactic locations. Among them, cool carbon stars are interesting because they have a photospheric C/O ratios that exceed 1, which makes all the oxygen in the photosphere gets locked with C to make CO molecule and remaining carbon bonds with N or H or C itself to make CH, CN, and C2. These molecular features can be identified in their spectra as distinct features of C2, CN and CH making their detection simple even in relatively low-resolution spectra. The newly installed TIFR-ARIES Near-infrared Spectrograph  (TANSPEC) on 3.6m Devasthal Optical Telescope (DOT) is a potential instrument to study such stellar populations as it offers a large wavelength coverage of 0.58 to 2.5 microns. In the talk, I will be discussing the preliminary results of the calibration runs and a few science cases that can be carried out using TANSPEC observations.
I will also discuss our recent observational study on CNO abundances in carbon enhanced metal-poor stars from the Milky Way halo. We used the  TIFR Near-Infrared Spectrometer and Imager (TIRSPEC) and Hanle Echelle spectrograph(HESP) mounted on 2m Himalayan Chandra Telescope (HCT) to carry out the study.