THE STAR-FORMATION HISTORY OF NGC-7252

The merger remnant NGC 7252 (= Arp 226) shows blue colours and an AF-t ype spectrum, indicating a major starburst about a billion years ago. Here we develop a quantitative model for the star formation history of this galaxy, using the merger starburst models developed in a compani on paper. Comparison with existing observations shows that in the case of NGC 7252 two fairly massive, more than 10 Gyr old Sc type spirals should have merged, inducing a strong starburst which increased the to tal stellar mass by 20 to 50% within (1 - 5).10(8) yr. With these para meters we obtain good agreement with the observed UBVR colours of NGC 7252, its luminosity and gas content, and with Schweizer's observed sp ectrum at a time of 1.3-2 Gyr after the beginning of the burst. Our mo del predicts NIR colours, gas abundances, and the spectrum of NGC 7252 from 1150 to 10.000 angstrom, which may be tested by future observati ons. Tighter constraints on the strength and duration of the burst tha n those from existing observations could be derived from gas abundance ratios. We follow the spectral, photometric, and chemical properties of our best fit NGC 7252 model until it evolves into an elliptical gal axy within the next few Gyr. Comparing the spectral age of greater tha n or similar to 1.3 Gyr with dynamical age estimates from Borne & Rich stone's models for the merger orbit suggests that burstlike star forma tion must have started greater than or similar to 0.5 Gyr before the f irst pericenter contact of the two disks. Thus in this case the burst is expected to have started when the progenitor's massive halos merged and ended before core merging was complete. The high burst strength r equired by our models to fit the observational data implies a star for mation efficiency high enough that globular clusters (GCs) may be form ed. We predict colours and stellar metallicities for such a secondary GC population to be compared to HST observations.