STAR-FORMATION IN EARLY-TYPE GALAXIES OF MIXED PAIRS

We present optical imaging, spectroscopy and stellar population synthe sis results for a sample of 4 mixed pairs of galaxies. The data allow us to estimate the degree of interaction with reasonable certainty. We conclude that one pair, AM1907-504, is likely to be an optical alignm ent. The remaining systems show radial velocity differences and morpho logy consistent with the hypothesis that they are physical binaries. S urface photometry allowed us to measure tidal distortions in the spira l components and to identify internal structure in the early-type memb ers. We also made a stellar population synthesis study of the early-ty pe components and find evidence for a young stellar population in the central regions of these galaxies. We consider possible origins for th e young component as due either to mass-transfer from the spiral (cros s-fuelling) or accretion events.