The planet search program at the ESO Coude Echelle spectrometer. III. The complete Long Camera survey results

TL;DR

This paper reports the comprehensive results of a planet search survey using the ESO CES instrument, analyzing radial velocity data for 37 stars, identifying variability, and setting upper limits on detectable planetary companions.

Contribution

It provides the complete data set and statistical analysis of a long-term radial velocity survey, including the first detection of an Earth-like orbit planet around a young star.

Findings

Identified long-term low-amplitude RV variables Beta Hyi and eps Ind.

Set upper mass limits for giant planets around 30 stars.

Demonstrated the survey's capability to detect short-period planets and continued observations without velocity corrections.

Abstract

We present the complete results of the planet search program carried out at the ESO Coude 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 (Kuerster et al. 2000). 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 eps 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 m sin 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.