Credit: (Top) NASA/Dana Berry; (Bottom) Carin Cain

Figure 1: (Top) Artist’s conception of an accreting neutron star in a binary system. Highly unstable, proton-rich isotopes are produced in x-ray bursts from the star via the so-called $rp$ process. These unstable isotopes subsequently decay to more stable isotopes and could be the source of some of the rare isotopes on Earth. (Bottom) Possible $rp$ process in the region of the nuclear chart where the SHIPTRAP group performed its measurements. The balance between proton radiative capture (p,$γ$)—where energy is released—and photodissociation ($γ$,p)—where energy is absorbed and a proton emitted—that create and destroy technetium-$87$, respectively, is highly sensitive to the nuclear masses involved. SHIPTRAP’s newly measured masses of technetium-$87$ and molybdenum-$86$, in particular, show that photodissociation is relatively strong enough to impede the flow of the reaction “upwards” and strengthen the beta decay branch into $A=86$ nuclei.