M giants with IGRINS

Cool stars, such as M giants, can only be analysed in the near-infrared (NIR) regime due to ubiquitous TiO features optical spectra of stars with Teff < 4000 K. In dust obscured regions, like inner bulge and Galactic Center, intrinsically bright giants observed NIR is an optimal option determine their stellar abundances. Due uncertainties photometric methods, a method parameters for from themselves needed. We have carried out new observations 44 giant (also APOGEE DR17) IGRINS (R=45,000) mounted on Gemini South telescope. also obtained HK band six nearby well-studied spectral library. Using this sample, we developed by synthesis using SME. The validated M-giants. demonstrate accuracy precision determining $\alpha$-element trends versus metallicity solar neighbourhood giants. effective temperatures that derive (tested 3400$\lesssim$ $\lesssim$4000\,K) agree excellently which indicates indeed high. For 43 neighborhood our Teff, logg, [Fe/H], $\xi_\mathrm{micro}$, [C/Fe], [N/Fe], [O/Fe] are unison mean differences scatter (our - APOGEE) -67$\pm$33 K, -0.31$\pm$0.15 dex, 0.02$\pm$0.05 0.22$\pm$0.13 km/s, -0.05$\pm$0.06 0.06$\pm$0.06 0.02$\pm$0.09 respectively. Mg, Si, Ca Ti consistent both DR17 same well GILD trends. find clear enhancement abundances thick disc stars.