Title: Origin of meteoritic stardust unveiled by a revised proton-capture rate of $^{17}$O,
Abstract: Stardust grains recovered from meteorites provide high-precision snapshots of
the isotopic composition of the stellar environment in which they formed.
Attributing their origin to specific types of stars, however, often proves
difficult. Intermediate-mass stars of 4-8 solar masses are expected to
contribute a large fraction of meteoritic stardust. However, no grains have
been found with characteristic isotopic compositions expected from such stars.
This is a long-standing puzzle, which points to serious gaps in our
understanding of the lifecycle of stars and dust in our Galaxy. Here we show
that the increased proton-capture rate of $^{17}$O reported by a recent
underground experiment leads to $^{17}$O/$^{16}$O isotopic ratios that match
those observed in a population of stardust grains, for proton-burning
temperatures of 60-80 million K. These temperatures are indeed achieved at the
base of the convective envelope during the late evolution of intermediate-mass
stars of 4-8 solar masses, which reveals them as the most likely site of origin
of the grains. This result provides the first direct evidence that these stars
contributed to the dust inventory from which the Solar System formed.