Speaker
Description
For over thirty years the LUNA (Laboratory for Underground Nuclear Astrophysics) collaboration has exploited the ultra-low background of the Gran Sasso National Laboratory (LNGS) to measure key nuclear reactions directly at the energies of astrophysical interest. With the 3.5 MV accelerator of the Bellotti Ion Beam Facility (IBF) now available underground at LNGS, LUNA extends its reach to the higher energies and beam intensities that characterise explosive stellar environments. I will present the experimental programme including the reactions involved in explosive nucleosynthesis. The ¹²C+¹²C fusion reaction, measured through its ¹²C(¹²C,p)²³Na and ¹²C(¹²C,α)²⁰Ne channels, governs carbon ignition and thus thermonuclear (type Ia) supernovae and superbursts. In parallel, the competing ²²Ne(α,γ)²⁶Mg and ²²Ne(α,n)²⁵Mg reactions fix the branching that sets the dominant neutron source for the s process in massive stars and during explosive shell burning. Together, these LUNA measurements sharpen the nuclear input to models of stellar explosions and their associated outflows.