Abstract :
Gamma-ray line astronomy is capable to probe recent and current nucleosynthesis in the nearby universe. Interstellar 26Al (τ=1.04 106 y) confirms currently-active nucleosynthesis in the Galaxy, and could be attributed to massive stars as dominating sources. Nearby or well-known 26Al emission regions are now studied in detail to test consistency of models for the evolution of groups of massive stars and their impacts on the ISM. Interesting directions are towards Cygnus, Vela, Orion, and Sco-Cen. 26Al line shape details, and measurement of correlated 60Fe may be needed to resolve the massive-star degeneracy and quantify specific 26Al sources. In spite of the 44Ti detection (τ=89 y) from the Cas A supernova remnant 44Ti gamma-rays from other young SNRs, such as SN1987A or otherwise occulted SNRs in the inner Galaxy or nearby active regions, are difficult. The apparent paucity of 44Ti sources seems to suggest that 44Ti ejection is from rather non-typical core-collapse supernovae. Spectral resolution of the 44Ti line shape with future instruments could be a unique SN/SNR diagnostic. Transients from nova nucleosynthesis positron annihilation, and 7Be or more longlived 22Na radioactivities still have to wait for future more sensitive instruments or nearby events. High spectral-resolution experiments such as INTEGRAL (launch Oct 2002) will address some of the open questions through measurements of nucleosynthesis gamma-ray line shapes.
