Sc and Mn abundances in disk and metal-rich halo stars

TL;DR

This study measures scandium and manganese abundances in 119 stars across different Galactic populations, revealing their distinct behaviors and potential nucleosynthesis origins, especially the role of supernovae types.

Contribution

It provides detailed abundance patterns of Sc and Mn in disk and halo stars, highlighting their different trends and suggesting possible nucleosynthesis sources.

Findings

Sc behaves like an alpha-element with decreasing [Sc/Fe] at higher metallicities.

Mn shows an increase in [Mn/Fe] with metallicity, with a notable jump at [Fe/H] = -0.7.

A dual pattern of [Sc/Fe] is observed in halo stars.

Abstract

Sc and Mn abundances are determined for 119 F and G main-sequence stars with -1.4 < [Fe/H] < +0.1, representing stars from the thin disk, the thick disk and the halo. The results indicate that Sc behaves like an alpha-element, showing a decreasing [Sc/Fe] with increasing metallicity in disk stars and a dual pattern in the kinematically selected halo stars. In contrast, Mn shows an increase from [Mn/Fe] = -0.5 at [Fe/H] = -1.4 to zero at solar metallicity. There appears to be a discontinuity or sharp increase of [Mn/Fe] at [Fe/H] = -0.7 corresponding to the transition between the thick and the thin disk. It is discussed if supernovae of Type Ia are a major source of Mn in the Galactic disk or if the trend of [Mn/Fe] vs. [Fe/H] can be explained by nucleosynthesis in Type II supernovae with a strong metallicity dependence of the yield.