  Aluminium-26 is a short-lived radionuclide with a half-life of 0.72Myr, which
is observed today in the Galaxy via gamma-ray spectroscopy and is inferred to
have been present in the early Solar System via analysis of meteorites. Massive
stars are considered the main contributors of Al26. Although most massive stars
are found in binary systems, the effect, however, of binary interactions on the
Al26 yields have not been investigated since Braun & Langer (1995). Here we aim
to fill this gap. We have used the MESA stellar evolution code to compute
massive (10Msun<=M<=80Msun), non-rotating, single and binary stars of solar
metallicity (Z=0.014). We computed the wind yields for the single stars and for
the binary systems where mass transfer plays a major role. Depending on the
initial mass of the primary star and orbital period, the Al26 yield can either
increase or decrease in a binary system. For binary systems with primary masses
up to ~35-40Msun, the yield can increase significantly, especially at the lower
mass-end, while above ~45Msun the yield becomes similar to the single star
yield or even decreases. Our preliminary results show that compared to
supernova explosions, the contribution of mass-loss in binary systems to the
total Al26 abundance produced by a stellar population is minor. On the other
hand, if massive star mass-loss is the origin of Al26 in the early Solar
System, our results will have significant implications for the identification
of the potential stellar, or stellar population, source.
