2020012

Massive stars and their impacts on their surrounding interstellar medium drive the stellar feedback process one of the main astrophysical issues in the context of galaxy evolution and cosmic chemical evolution. Radioactivity from 26Al adds a unique diagnostic tool for its investigation in nearby massive-star regions. The Orion region hosts one of the closest such regions at a distance of 400 pc. COMPTEL had supported such opportunity through detection of 26Al 1809 keV emission from this region. An interesting offset of the diffuse and extended 26Al emission source from its likely sources suggests champagne-like outflow from the OB1 association stars into the Eridanus cavity. HI filaments in radio emission X-ray emission seen with XMM-Newton and GeV emission seen with Fermi-LAT and simulations support this interesting scenario. Recently-improved details with Gaia on the stellar population and HI and CO analyses on gas make a multi-messenger study of feedback particularly promising here i.e. how the ISM is shaped by massive stars and the interaction of massive stars with their surrounding ISM: With INTEGRAL gamma-ray measurements we can constrain 26Al ejection from massive stars in mass and velocity and due to their proximity and location on the near side of molecular clouds and at the edge of a large cavity we can compare the locations of massive stars to the morphology of the ISM and the emission pattern of 26Al radioactivity. Analysis of previous INTEGRAL observations has already obtained a firm detection of the expected signal from 26Al. Our proposed further multi-year deepening of exposure (3 Ms in AO-19 and AO-20) aims to truly establish our measure of the line shape and thus kinematics of this nearby 26Al source. With these observations we can also search for annihilation radiation and for the intensity of nuclear deexcitation gamma-rays in the MeV range both valuable diagnostics of the structure of s [truncated! Please see actual data for full text]