We present the result of radial velocity observation of a W UMa type binary star EX Leo. We observed the star on February 16, 2003, using Long-Slit spectrograph of BOAO(Bohyunsan Optical Astronomical Observatory). Since the spectral lines are broad due to its fast rotation, it is difficult to distinguish two radial velocities from cross correlation function. Instead of cross correlation function, we used broadening function to develop our own code which estimate the radial velocity of the broadened line spectra. With our own code, radial velocities of primary and secondary stars are derived simultaneously. From the radial velocity curve fit, we obtained K1=50.24±8.29km/s and K2=254.05±20.984km/s respectively.

• 강동일(한국교원대학교, 천문연구원) | DONG-IL KANG (Korea National University of Education, Korea Astronomy Observatory)
• 박홍서(한국교원대학교) | HONG-SUH PARK (Korea National University of Education)
• 한인우(천문연구원) | INWOO HAN (Korea Astronomy Observatory)
• 김강민(천문연구원) | KANG-MIN KIM (Korea Astronomy Observatory)