Planetary Companions to HD 136118, HD 50554, and HD 106252

Abstract

Precise Doppler observations at Lick Observatory have revealed a substellar companion orbiting the F9 V star HD 136118 with an orbital period P = 1209 ± 24 days, velocity semiamplitude K = 212 ± 6 m s -1 , and eccentricity of 0.37 ± 0.025. The assumed stellar mass of 1.24 M ⊙ yields a Keplerian companion with M sin i = 11.9 M J and semimajor axis of 2.3 AU. We also confirm the orbital solutions for two previously announced planets, one orbiting the F8 V star HD 50554 and one orbiting the GO V star HD 106252. Our orbital solution for HD 50554 yields P = 1254 ± 34 days, K = 78.5 ?± 6.7 m s -1 , and e = 0.51 ± 0.06. The assumed stellar mass of 1.065 M ⊙ implies a companion mass M sin i = 3.7 M J and semimajor axis of 2.2 AU. For HD 106252, we find P = 1503.3 ± 62 days, K = 150.9 ± 25 m s -1 , and eccentricity e = 0.57 ± 0.11. The assumed stellar mass of 0.96 M ⊙ implies M sin i = 6.96 M J , and semimajor axis of 2.42 AU.