Relics of Subluminous Supernovae in Metal-poor Stars

The unique elemental abundance pattern of the carbon-rich stars CS 29498-043 and CS 22949-037 is characterized by a large excess of magnesium and silicon in comparison with iron. This excess is investigated in the context of a supernova-induced star formation scenario, and it is concluded that these stars were born from the matter swept up by supernova remnants containing little iron and that such supernovae are similar to the least luminous supernovae ever observed, SNe 1997D and 1999br. Comparison of the observed abundance pattern in iron group elements of subluminous supernovae with those of other supernovae leads to intriguing implications for explosion, nucleosynthesis, and mixing in supernovae. The observed invariance of these ratios cannot be accounted for by a spherically symmetric supernova model.