摘要：The N2K planet search program was designed to exploit the planet-metallicity correlation by searching for gas giant planets orbiting metal-rich stars. Here, we present the radial velocity measurements for 378 N2K target stars that were observed with the HIRES spectrograph at Keck Observatory between 2004 and 2017. With this data set, we announce the discovery of six new gas giant exoplanets: a double-planet system orbiting HD148164 ( M i sin of 1.23 and 5.16M JUP ) and single planet detections around HD55696 ( M i sin =3.87M JUP ), HD98736 ( M i sin = 2.33M JUP ), HD203473 ( M i sin =7.8M JUP ), and HD211810 ( M i sin =0.67M JUP ). These gas giant companions have orbital semimajor axes between 1.0 and 6.2au and eccentricities ranging from 0.13 to 0.71. We also report evidence for three gravitationally bound companions with M i sin between 20 and 30M JUP , placing them in the mass range of brown dwarfs, around HD148284, HD214823, and HD217850, and four low-mass stellar companions orbiting HD3404, HD24505, HD98630, and HD103459. In addition, we present updated orbital parameters for 42 previously announced planets. We also report a nondetection of the putative companion HD 73256 b. Finally, we highlight the most promising candidates for direct imaging and astrometric detection, and we find that many hot Jupiters from our sample could be detectable by state-of-the-art telescopes such as Gaia.
关键词：planets and satellites: detection;surveys;techniques: radial velocities
