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In the 90's, theoretical studies motivated the use of the asymptotic-giantbranch bump (AGBb) as a standard candle given the weak dependence between itsluminosity and stellar metallicity. Because of the small size of observedasymptotic-giant branch (AGB) samples, detecting the AGBb is not an easy task.However, this is now possible thanks to the wealth of data collected by theCoRoT, Kepler, and TESS space-borne missions. It is well-know that the AGB bumpprovides valuable information on the internal structure of low-mass stars,particularly on mixing processes such as core overshooting during the coreHe-burning phase. In this context, we analysed ~ 4,000 evolved giants observedby Kepler and TESS, including red-giant branch stars and AGB stars, for whichasteroseismic and spectrometric data are available. By using statisticalmixture models, we detected the AGBb both in frequency at maximum oscillationpower and in effective temperature. Then, we used the Modules for Experimentsin Stellar Astrophysics MESA stellar evolution code to model AGB stars andmatch the AGBb occurrence with observations. From observations, we could derivethe AGBb location in 15 bins of mass and metallicity. We noted that the higherthe mass, the later the AGBb occurs in the evolutionary track, which agreeswith theoretical works. Moreover, we found a slight increase of the luminosityat the AGBb when the metallicity increases, which complicates the use of theAGBb as a standard candle. By fitting those observations with stellar models,we noticed that low-mass stars (M < 1.0 $M_{\odot}$) require a small coreovershooting region during the core He-burning phase. This core overshootingextent increases toward high mass, but above M > 1.5 $M_{\odot}$ we found thatthe AGBb location cannot be reproduced with a realistic He-core overshootingalone, and instead additional mixing processes have to be invoked.

Characterising the AGB bump and its potential to constrain mixing processes in stellar interiors