Stars

Detections of lithium (and in one case, potassium) in the atmospheres of four old white dwarfs suggest that they have accreted fragments of planets; specifically, planetary crusts. One white dwarf evolved from an intermediate-mass progenitor, indicating that rocky planets form even around short-lived B-type stars.

Stars in the Tucana II ultrafaint dwarf galaxy observed out to nine half-light radii reveal the presence of an extended dark matter halo with a total mass of >10⁷ solar masses, consistent with a generalized Navarro–Frenk–White density profile and suggestive of past strong bursty feedback or an early galactic merger.

The factors affecting how and why supernovae occur are discussed, and the current status of core-collapse supernova explosion theory is reviewed.

The triple-α reaction rate in proton-rich core-collapse supernovae is found to be enhanced at high nucleon densities, suppressing the formation of proton-rich nuclei from gallium to cadmium.

Direct experimental evidence of the carbon–nitrogen–oxygen fusion cycle in the Sun is provided by the detection of neutrinos emitted during this process.

Observations and stellar evolution models of a blue ring nebula and its central star (TYC 2597-735-1) suggest that the remnant star merged with a lower-mass companion several thousand years ago.