• Jenkins, J. S.
;
• Jones, H. R. A.
;
• Tinney, C. G.
;
• Butler, R. P.
;
• McCarthy, C.
;
• Marcy, G. W.
;
• Pinfield, D. J.
;
• Carter, B. D.
;
• Penny, A. J.

Abstract

We have acquired high-resolution echelle spectra of 225 F6-M5 type stars in the Southern hemisphere. The stars are targets or candidates to be targets for the Anglo-Australian Planet Search. CaII H& K line cores were used to derive activity indices for all of these objects. The indices were converted to the Mt. Wilson system of measurements and logR'_HK values determined. A number of these stars had no previously derived activity indices. In addition, we have also included the stars from Tinney et al. using our Mt. Wilson calibration. The radial-velocity instability (also known as jitter) level was determined for all 21 planet-host stars in our data set. We find the jitter to be at a level considerably below the radial-velocity signatures in all but one of these systems. 19 stars from our sample were found to be active (logR'_HK > -4.5) and thus have high levels of jitter. Radial-velocity analysis for planetary companions to these stars should proceed with caution.