HD 222925: a New Opportunity to Explore the Astrophysical and Nuclear Conditions of r-process Sites

Understand

With the most trans-iron elements detected of any star outside the Solar System, HD 222925 represents the most complete chemical inventory among r-process-enhanced, metal-poor stars.

• While the abundance pattern of the heaviest elements identified in HD 222925 agrees with the scaled Solar r-process residuals, as is characteristic of its r-process-enhanced classification, the newly measured lighter r-process elements display marked differences from their Solar counterparts.
• In this work, we explore which single astrophysical site (if any) produced the entire range of elements ($34\leq Z\leq 90$) present in HD 222925.
• We find that the abundance pattern of lighter r-process elements newly identified in HD 222925 presents a challenge for our existing nucleosynthesis models to reproduce.