Unique Stellar Chemistry of Star A980:
Scientists at the Indian Institute of Astrophysics (IIA), Bengaluru identified a rare helium-rich star (A980) exhibiting a rare chemical composition, challenging existing models of stellar evolution and nucleosynthesis.A980 lies in the Ophiuchus constellation, about 25,800 light years from Earth. It shows the first-ever detection of singly-ionized germanium (Ge II) in an EHe star, with germanium levels eight times higher than in the Sun. A980 is a cool Extreme Helium (EHe) star, a rare class of evolved stars made almost entirely of helium with little to no hydrogen, typically formed through the merger of a helium-rich and a carbon-oxygen rich white dwarf. Stellar models explain how stars form, evolve, and create elements. They suggest heavy elements like germanium form in supernovae or AGB stars, not in Extreme Helium (EHe) stars. However, Star A980, an EHe star, shows unusually high germanium levels, challenging these models. It suggests that element formation may happen during white dwarf mergers, a process not well covered in current theories, indicating the need to revise stellar evolution models.
