We present results of a new high-resolution spectroscopic study of the RS CVn-type binary system EI Eridani (HD26337). We used high S/N ratio LSD profiles to measure a new RV orbit of the primary component and new orbital parameters. We found evidence of strong spectral line profile variations at time intervals indicating the existence of short-lived (few days) spots on the surface of the primary component. We measured a projected rotation velocity of star of 53.2 km/s

ABSTRACT
1. INTRODUCTION
2. OBSERVATIONS
3. ORBITAL RADIAL VELOCITIES AND ROTATION
4. CONCLUSION
REFERENCES

• J.Keeratibharat(Department of Physics and Materials Science, Faculty of Science, Chiang Mai University)
• D.E.Mkrtichian(National Astronomical Research Institute of Thailand/Crimean Astrophysical Observatory, Taras Shevchenko National University of Kyiv)
• S.Komonjinda(Department of Physics and Materials Science, Faculty of Science, Chiang Mai University)