# Contribution of type Ia supernovae to the chemical enrichment of the ultra-faint dwarf galaxy Bootes I

## TL;DR

This study analyzes chemical abundances in stars of the ultra-faint dwarf galaxy Bootes I, revealing the influence of Type Ia supernovae on its chemical evolution and providing a detailed dataset for such galaxies.

## Contribution

It presents the largest homogeneous chemical abundance dataset for Bootes I, highlighting the transition in alpha-element ratios indicating Type Ia supernovae contribution.

## Key findings

- Transition from alpha overabundance to solar ratio at -3<[Fe/H]<-2
- First detailed chemical abundance analysis of multiple stars in Bootes I
- Evidence of iron production from Type Ia supernovae in ultra-faint dwarf galaxy

## Abstract

For three stars in the ultra-faint dwarf (UFD) galaxy Bootes I we have determined the atmospheric parameters, performed a new reduction of high-resolution spectra from the Subaru archive, and derived the abundances of eight chemical elements without using the LTE assumption. As a result, among the galaxies of its class Bootes I now has the largest sample of stars (11) with a homogeneous set of atmospheric parameters and chemical abundances, and this makes it the most promising for studying the chemical evolution of UFD galaxies. We show that in the range -3<[Fe/H]<-2 for each of the three $\alpha$--process elements, magnesium, calcium, and titanium, a transition from their overabundance relative to iron with [$\alpha$/Fe]$\approx$0.3 to the solar [$\alpha$/Fe] ratio occurs. This most likely suggests the commenced production of iron in type Ia supernovae. The behaviour of the carbon, sodium, nickel, and barium abundances does not differ from that in more massive galaxies, our Galaxy and classical dwarf spheroidal galaxies.