The planet search program at the ESO Coudé Echelle spectrometer

Abstract

We present the complete results of the planet search program carried out at the ESO Coudé Echelle Spectrometer (CES) on La Silla, using the Long Camera from Nov. 1992 to April 1998. The CES survey has monitored 37 late-type (F8V - M5V) stars in the southern hemisphere for variations in their differential radial velocities (RV) in order to detect Doppler reflex motions caused by planetary companions. This led to the discovery of the first extrasolar planet in an Earth-like orbit around the young (ZAMS) and active G0V star iota Horologii (Kürster et al. \cite{martin00}). Here we present the RV results for all survey stars and perform a statistical examination of the whole data-set. Each star is tested for RV variability, RV trends (linear and non-linear) and significant periodic signals. beta Hyi and epsilon Ind are identified as long-term, low-amplitude RV variables. Furthermore, for 30 CES survey stars we determine quantitative upper mass-limits for giant planets based on our long-term RV results. We find that the CES Long Camera survey would have detected short-period (``51 Peg-type'') planets around all 30 stars but no planets with msin i < 1 {M}_Jup at orbital separations larger than 2 AU. Finally, we demonstrate that the CES planet search can be continued without applying velocity corrections to the RV results coming from the currently installed Very Long Camera at the CES. Based on observations collected at the European Southern Observatory, La Silla. Appendices A and B are only available in electronic form at http://www.edpsciences.org