s-process polluted binaries in GALAH DR4

We compare our stellar parameters and individual abundances with those of the survey and use this validation to define the thresholds that a star in GALAH DR4 must pass to be flagged as a good s-process-rich candidate. Based on our comparisons with the high resolution complementary spectra, we define thresholds on 5 quantities: [s/Fe]>0.40dex, [Y/Fe]>0.22dex, [Zr/Fe]>0.26dex, [Ba/Fe]>0.19dex, and La/Fe]>0.26dex. Results.

We identified 1059 stars in GALAH DR4 that are good candidates to be s-process polluted stars, covering a broad parameter space (4000K<Teff<6000K, 0.5dex<logg<5.0dex, -2.0dex<[Fe/H]<0.5dex). They share many similarities with the samples of confirmed s-rich stars, especially their ratios of heavy over light s-elements ([hs/ls]), which strengthen our confidence in the purity of the sample. When crossmatching the sample with the literature, we find that only 7% of the candidates have measured orbital periods and eccentricities, limiting for now a full comparison with confirmed Ba and related star samples.

However, their binary fraction is, as expected, higher than the one we found for the full GALAH DR4 catalogue. Our sample of candidates is almost five times larger than the number of currently confirmed polluted stars. This and the fact that it has been homogeneously treated by the GALAH survey open very interesting avenues to confront nucleosynthesis models as well as binary evolution models.