The components of the wide binary HD 219542 were recently found to differ in
metallicity by about 0.1 dex (Gratton et al. A&A 377, 123). In this paper, we
present the results of 2 years of high precision radial velocity monitoring of
these stars performed at the Telecopio Nazionale Galileo (TNG) using the high
resolution spectrograph SARG. No indication for radial velocity variations
above the measurement errors (5 m/s) was found for the metal richer component
A. This allows us to place upper mass-limits for planets around this star. HD
219542B instead shows a low amplitude variation with a 112 day period at a
confidence level of about 96-97%. This might suggest the presence of a
Saturn-mass planet, although it is still possible that these variations are due
to moderate activity of the star. Tests based on variations of bisectors,
stellar magnitude and line equivalent widths were inconclusive so far.Comment: 15 pages, 16 figures, A&A, in pres
