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Radial velocities, elemental abundances, and accretion properties of membersof star-forming regions (SFRs) are important for understanding star and planetformation. While infrared observations reveal the evolutionary status of thedisk, optical spectroscopy is fundamental to acquire information on theproperties of the central star and on the accretion characteristics. 2MASSarchive data and the Spitzer c2d survey of the Chamaeleon II dark cloud haveprovided disk properties of a large number of young stars. We complement thesedata with spectroscopy with the aim of providing physical stellar parametersand accretion properties. We use FLAMES/UVES+GIRAFFE observations of 40 membersof Cha II to measure radial velocities through cross-correlation technique, Liabundances by means of curves of growth, and for a suitable star elementalabundances of Fe, Al, Si, Ca, Ti, and Ni using the code MOOG. From theequivalent widths of the Halpha, Hbeta, and the HeI-5876, 6678, 7065 Angstromemission lines, we estimate the mass accretion rates, dMacc/dt, for all theobjects. We derive a radial velocity distribution for the Cha II stars(<Vrad>=11.4+-2.0 km/s). We find dMacc/dt prop. to Mstar^1.3 and to Age^(-0.82)in the 0.1-1.0 Msun mass regime, and a mean dMacc/dt for Cha II of ~7*10^(-10)Msun/yr. We also establish a relationship between the HeI-7065 Angstrom lineemission and the accretion luminosity. The radial velocity distributions ofstars and gas in Cha II are consistent. The spread in dMacc/dt at a givenstellar mass is about one order of magnitude and can not be ascribed entirelyto short timescale variability. Analyzing the relation between dMacc/dt and thecolors in Spitzer and 2MASS bands, we find indications that the inner diskchanges from optically thick to optically thin at dMacc/dt~10^(-10) Msun/yr.Finally, the disk fraction is consistent with the age of Cha II.

The Chamaeleon II low-mass star-forming region: radial velocities, elemental abundances, and accretion properties