  We present the results of contemporaneous spectroscopic and photometric
monitoring of the young solar-type star HD171488 (Prot~1.337 d) aimed at
studying surface inhomogeneities at photospheric/chromospheric levels. Echelle
FOCES spectra (R~40000) and Johnson photometry have been performed in 2006.
Spectral type, rotational velocity, metallicity, and gravity were determined
using a code developed by us. The metallicity was measured from the analysis of
iron lines. The spectral subtraction technique was applied to the most relevant
chromospheric diagnostics included in the FOCES spectral range (CaII IRT,
Halpha, HeI-D3, Hbeta, CaII H&K). A model with two large high-latitude spots is
sufficient to reproduce the B/V light curves and the radial velocity
modulation, if a temperature difference between photosphere and spots of 1500 K
is used. A Doppler imaging analysis of photospheric lines confirms a similar
spot distribution. With the help of an analogous geometric two-spot model, we
are able to reproduce the modulations in the residual chromospheric emissions
adopting different values of ratios between the flux of plages and quiet
chromosphere (5 for Halpha and 3 for CaII). Facular regions of solar type
appear to be the main responsible for the modulations of chromospheric
diagnostics. Both the spot/plage model and the cross-correlation between the
light curve and the chromospheric line fluxes display a lead effect of plages
with respect to spots (20-40 deg in longitude). The active regions of the
rapidly rotating star HD171488 are similar to the solar ones in some respect,
because the spot temperature is close to that of sunspot umbrae and the plage
flux-contrast is consistent with the average solar values. The main differences
with respect to the Sun are larger sizes and higher latitudes.
