We report the detection of an exoplanet candidate in orbit around σ Persei from a radial velocity (RV) survey. The system exhibits periodic RV variations of 579.8 ± 2.4 days. The purpose of the survey is to search for low-amplitude and long-period RV variations in giants and examine the origin of the variations using the fiber-fed Bohyunsan Observatory Echelle Spectrograph installed at the 1.8- m telescope of Bohyunsan Optical Astronomy Observatory in Korea. We present high-accuracy RV measurements of σ Per made from December 2003 to January 2014. We argue that the RV variations are not related to the surface inhomogeneities but instead a Keplerian motion of the planetary companion is the most likely explanation. Assuming a stellar mass of 2.25 ± 0.5 M⊙, we obtain a minimum planetary companion mass of 6.5 ± 1.0 MJup, with an orbital semi-major axis of 1.8 ± 0.1 AU, and an eccentricity of 0.3 ± 0.1 around σ Per.

ABSTRACT
1. INTRODUCTION
2. OBSERVATIONS AND REDUCTION
3. STELLAR CHARACTERISTICS
    3.1 Fundamental Parameters
    3.2 Stellar Mass
    3.3 Rotational Velocity
4. RADIAL VELOCITY VARIATIONS AND ORIGIN
    4.1 Orbital Solutions
    4.2 Chromospheric Activities
    4.3 Photometric Variations
    4.4 Line Bisector
5. DISCUSSION
REFERENCES

• BYEONG-CHEOL LEE(Korea Astronomy and Space Science Institute, Astronomy and Space Science Major, University of Science and Technology) Corresponding Author
• MYEONG-GU PARK(Department of Astronomy and Atmospheric Sciences, Kyungpook National University)
• DAVID E. MKRTICHIAN(National Astronomical Research Institute of Thailand, Crimean Astrophysical Observatory, Taras Shevchenko National University of Kyiv)
• GWANGHUI JEONG(Korea Astronomy and Space Science Institute)
• KANG-MIN KIM(Korea Astronomy and Space Science Institute)
• GENNADY VALYAVIN(Special Astrophysical Observatory, Russian Academy of Sciences)
• INWOO HAN(Korea Astronomy and Space Science Institute)