  We report the discovery by the HATSouth survey of HATS-4b, an extrasolar
planet transiting a V=13.46 mag G star. HATS-4b has a period of P = 2.5167 d,
mass of Mp = 1.32 Mj, radius of Rp = 1.02 Rj and density of rho_p = 1.55 +-
0.16 g/cm^3 ~ 1.24 rhoj. The host star has a mass of 1.00 Msun, a radius of
0.92 Rsun and a very high metallicity [Fe/H]= 0.43 +- 0.08. HATS-4b is among
the densest known planets with masses between 1-2 Mj and is thus likely to have
a significant content of heavy elements of the order of 75 Mearth. In this
paper we present the data reduction, radial velocity measurement and stellar
classification techniques adopted by the HATSouth survey for the CORALIE
spectrograph. We also detail a technique to estimate simultaneously vsini and
macroturbulence using high resolution spectra.
