The HARPS search for southern extra-solar planets VII.: A very hot Jupiter orbiting HD 212301

We report the discovery of a planetary companion orbiting the F8V star HD212301. This is the first very hot Jupiter discovered by a radial velocity survey. The detection was made possible by the HARPS spectrograph installed at the ESO 3.6 m telescope in Cerro La Silla, Chile. The data were carefully analyzed to exclude activity induced effects on the measured radial velocities. Although no transit has been detected, radial velocity oscillations are best explained with a planet of mass m(2) sin i = 0.45 M-Jupiter orbiting the star at 0.036 AU with a period of 2.246 days.