Context : The Scorpius-Centaurus association is the most-nearby group of massive and young stars .
As nuclear-fusion products are ejected by massive stars and supernovae into the surrounding interstellar medium , the search for characteristic \gamma -rays from radioactivity is one way to probe the history of activity of such nearby massive stars on a My time scale through their nucleosynthesis . ^ { 26 } Al decays with a radioactivity lifetime \tau \sim 1 My , 1809 keV \gamma -rays from its decay can be measured with current \gamma -ray telescopes .

Aims : We aim to identify nucleosynthesis ejecta from the youngest subgroup of Sco-Cen stars , and interpret their location and bulk motion from ^ { 26 } Al observations with INTEGRAL ’ s \gamma -ray spectrometer SPI .

Methods : Following earlier ^ { 26 } Al \gamma -ray mapping with NASA ’ s Compton observatory , we test spatial emission skymaps of ^ { 26 } Al for a component which could be attributed to ejecta from massive stars in the Scorpius-Centaurus group of stars .
Such a model fit of spatial distributions for large-scale and local components is able to discriminate ^ { 26 } Al emission associated with Scorpius-Centaurus , in spite of the strong underlying nucleosynthesis signal from the Galaxy at large .

Results : We find an ^ { 26 } Al \gamma -ray signal above 5 \sigma significance , which we associate with the locations of stars of the Sco-Cen group .
The observed flux of 6 10 ^ { -5 } ph cm ^ { -2 } s ^ { -1 } corresponds to \sim 1.1 10 ^ { -4 } M _ { \odot } of ^ { 26 } Al .
This traces the nucleosynthesis ejecta of several massive stars within the past several million years .

Conclusions : We confirm through direct detection of radioactive ^ { 26 } Al the recent ejection of massive-star nucleosynthesis products from the Sco-Cen association .
Its youngest subgroup in Upper Scorpius appears to dominate ^ { 26 } Al contributions from this association .
Our ^ { 26 } Al signal can be interpreted as a measure of the age and richness of this youngest subgroup .
We also estimate a kinematic imprint of these nearby massive-star ejecta from the bulk motion of ^ { 26 } Al and compare this to other indications of Scorpius-Centaurus massive-star activity .