Yonsei Spectroscopic Survey for Bulge Red Clump Stars

In order to understand the origin of the double red clump (RC) observed in the color-magnitude diagram of the Milky Way bulge, we are undertaking spectroscopic surveys for the RC stars in different latitude and longitude fields of the bulge. Low-resolution multi-object spectroscopy for CN, CH, and Ca indices is being performed with LCO 2.5m and Gemini south 8.1m telescopes, while high-resolution spectroscopy for Na and O abundances is being carried out with the M2FS instrument on the Magellan 6.5m telescope. In this talk, we will present our first results from LCO 2.5m and Magellan 6.5m telescopes, together with our future observing strategies for these surveys.