Find a nucleosynthesis model that reproduces J0931+0038’s full abundance pattern

Determine whether any specific nucleosynthesis scenario for an early, metal-poor massive star can simultaneously reproduce the complete observed chemical abundance pattern of 2MASS J09311004+0038042 (J0931+0038)—including the extreme odd–even effect from carbon to scandium, very low [Sc/Ti/V/Fe], enhanced [Mn/Ni/Zn/Fe], and strong first neutron-capture peak elements (Sr–Pd) with extremely low [Ba/Fe]—at metallicity [Fe/H] = −1.76, without violating dilution and metallicity constraints.

Background

The paper presents the discovery of J0931+0038, a metal-poor star with an unusually high metallicity and an extreme abundance pattern that combines several rare features previously only seen individually in very metal-poor stars. The authors conduct an extensive comparison with multiple nucleosynthesis model grids (core-collapse supernovae, hypernovae, pair-instability supernovae) and find partial matches to subsets of elements but no single model explaining all observed features.

Because the star’s metallicity implies enrichment by a single event and because the Fe-peak and neutron-capture patterns impose strict, sometimes conflicting constraints, the absence of a complete model represents a central unresolved issue highlighted by the authors.