New planetary systems from the Calan–Hertfordshire Extrasolar Planet Search

Abstract

We report the discovery of eight new giant planets, and updated orbits for\nfour known planets, orbiting dwarf and subgiant stars using the CORALIE, HARPS,\nand MIKE instruments as part of the Calan-Hertfordshire Extrasolar Planet\nSearch. The planets have masses in the range 1.1-5.4MJs, orbital periods from\n40-2900 days, and eccentricities from 0.0-0.6. They include a double-planet\nsystem orbiting the most massive star in our sample (HD147873), two eccentric\ngiant planets (HD128356b and HD154672b), and a rare 14 Herculis analogue\n(HD224538b). We highlight some population correlations from the sample of\nradial velocity detected planets orbiting nearby stars, including the mass\nfunction exponential distribution, confirmation of the growing body of evidence\nthat low-mass planets tend to be found orbiting more metal-poor stars than\ngiant planets, and a possible period-metallicity correlation for planets with\nmasses >0.1MJ, based on a metallicity difference of 0.16 dex between the\npopulation of planets with orbital periods less than 100 days and those with\norbital periods greater than 100 days.\n