In his new paper as first author, our NEFERTITI’s member David Aguado, showed that the star SMSS1605-1443 is a truly second-generation object dwelling in a binary system. SMSS1605-1443 is one of the most pristine stars known, with an iron content ~ 1 million times smaller than our Sun and a higher carbon abundance. This star pertain to the so-called CEMP-no stars (no barium), which are very common at the lowest [Fe/H]. Thanks to the exceptional resolution of the ESPRESSO spectrograph at the VLT, David et al. showed that SMSS1605-1443 has a binary companion, which however did not affected his chemical composition. Indeed, the very high 12C/13C isotopic ratio measured with ESPRESSO reveals that this is a truly second-generation stars, which formed out of gas directly polluted by first stars of tens of solar masses that exploded as low energy supernovae.
Aguado et al. (including Salvadori) 2023, A&A, 669, L4
Italian Press releases (UNIFI & media INAF)