  Products from massive-star nucleosynthesis have been measured with SPI on
INTEGRAL: Characteristic gamma-ray lines from radioactive decays of long-lived
26Al and 60Fe isotopes, and from 44Ti decay (decay time 89y). Detections of
both these isotopes has laid the foundation to peek into massive-star
interiors, through different views at those measurements. The gamma-ray flux
can be converted into amounts of these radioactive isotopes, but the
constraints which derive from this for massive star models involve additional
steps. -- Earlier results had demonstrated the basic constraints inherent to
such radioactivity data, i.e. detection of 26Al is a calibration for
massive-star yields, 60Fe enables an isotopic-yield ratio test eliminating
modeling and observing bias aspects, and 44Ti searches showed that its
production does not occur homogeneously over core-collapse events. The current
status of 26Al and 60Fe observations and their analysis is reaching a threshold
for astrophysical insights: Specific regions of massive star groups and their
radioactivity gamma-rays have recently been investigated, such as Sco-Cen and
Orion. As for 44Ti, spectroscopical information constrains ejection velocities
of these inner supernova ejecta for the Cas A event. These parameters for
massive stars can be related to other fields of astronomy, of nuclear physics
experiments and theory, and of theoretical astrophysics. Thus, model
improvements appear on the horizon, as e.g. implemented in the EuroGenesis
program framework of the European Science Foundation.
