Fundamental parameters of the moderately young open clusters NGC 5999, NGC6031, Ruprecht 115 and Ruprecht 120

We present CCD BVI Johnson-Cousins photometry for the southern open cluster s NGC 5999, NGC 6031, Ruprecht 115 and Ruprecht 120, The sample consists of about 1160 stars reaching down to V similar to 19 mag. From the analysis o f the colour-magnitude diagrams, we confirm the reality of the clusters and derive their fundamental parameters (reddening, distance and age). We also present integrated spectra for NGC 6031,Ruprecht 115 and Ruprecht 120, cov eting a range from 3500 to 9200 Angstrom. From the equivalent widths of Bal mer and infrared Ca II triplet lines, as well as from a comparison of the o btained spectra with those of template clusters, we derive reddening, age a nd metallicity. The photometric and spectroscopic results allow us to concl ude that the four clusters are moderately young (age similar to 100-500 Myr ) and are located approximately towards the Galactic Centre at similar to 2 .3 kpc from the Sun. NGC 6031 and Ruprecht 120 have nearly solar metal cont ent, while Ruprecht 115 appears to be slightly metal-rich.