Pupin Physics Laboratories

It has long been observed that compared to per cent of solar twins, the Sun exhibits a depletion in the elemental abundance of refractory elements (such as Fe, Ti, and Al),1 and this depletion is correlated with the condensation temperature (e.g. Meléndez et al. 2009; Bedell et al. 2018; Rampalli et al. 2024). Similar phenomena have also been observed and validated in other stars (e.g. Ramírez et al. 2010; Ramírez, Meléndez & Asplund 2014; Liu et al. 2020, 2024; Flores et al. 2024).

The growth of spectroscopic data of the Milky Way has launched an industry in Galactic archaeology. Measurements of stellar parameters, velocities, element abundances, and ages of stars serve as the information to reconstruct Galactic history (see Bland-Hawthorn & Gerhard 2016; Helmi 2020; Deason & Belokurov 2024, and references therein). Gaia (Gaia Collaboration 2018) has transformed the empirical characterization of the Milky Way, on many scales.

Analysing stellar parameters and abundances from nearly one million Gaia DR3 Radial Velocity Spectrometer (RVS) spectra poses challenges due to the limited spectral coverage (restricted to the infrared Ca ii triplet) and variable signal-to-noise ratios of the data. To address this, we use The Cannon, a data-driven method, to transfer stellar parameters and abundances from the GALAH Data Release 4 (DR4; R ∼ 28 000) catalogue to the lower resolution Gaia DR3 RVS spectra (R ∼ 11,500).