A detailed view of the gas shell around R Sculptoris with ALMA

Context. During the asymptotic giant branch (AGB) phase, stars undergo thermal pulses − short-lived phases of explosive helium burning in a shell around the stellar core. Thermal pulses lead to the formation and mixing-up of new elements to the stellar surface. They are hence fundamental to the chemical evolution of the star and its circumstellar envelope. A further consequence of thermal pulses is the formation of detached shells of gas and dust around the star, several of which have been observed around carbon-rich AGB stars.