Abstract We present detailed chemical abundances of the brightest star in each of the ultrafaint dwarf galaxies Eridanus IV and Centaurus I using high-resolution Magellan/MIKE spectroscopy. The brightest star in Centaurus I, CenI-5136, is a very metal-poor star with metallicity Fe/H = −2.52 ± 0.17 and chemical abundances typical of a star in an ultrafaint dwarf galaxy. We confirm that the star in Eridanus IV, EriIV-9808, is extremely metal poor (Fe/H = −3.25 ± 0.19) and find that it is carbon enhanced (C/Fe = 1.07 ± 0.34), as is common for many stars at this metallicity. Both stars are also neutron-capture deficient, which is typical of stars in ultrafaint dwarf galaxies, but less common in other environments. We consider possible enrichment scenarios for EriIV-9808 and tentatively conclude that it is unlikely to be the descendant of a single Population III progenitor, despite its carbon enhancement and low metallicity.
Heiger et al. (Wed,) studied this question.