Extreme Helium (EHe) stars

Extreme Helium (EHe) stars

Why it Matters? 

  • Indian scientists at the Indian Institute of Astrophysics (IIA), Bengaluru, discovered germanium in A980, a rare Extreme Helium Star (EHe), using the Himalayan Chandra Telescope, marking the first such detection and opening new frontiers in stellar chemistry. 

What You Should Know? 

  • Extreme Helium Star (EHe) is a low-mass supergiant star that is almost devoid of hydrogen. 

  • These rare stars primarily consist of helium instead of hydrogen, which is the main element in typical stars like the Sun. 

  • Extreme Helium Stars are believed to originate from the merger of a carbon-oxygen white dwarf with a less massive helium white dwarf. 

  • Only 21 Extreme Helium Stars have been detected so far in our Milky Way Galaxy. 

  • These stars have effective surface temperatures ranging from 8,000 Kelvin to 35,000 Kelvin. 

  • The first Extreme Helium Star, HD 124448, was discovered in 1942 by Daniel M. Popper at McDonald Observatory, Austin, from the University of Chicago. 

A980

  • It is a rare Extreme Helium Star (EHe) located in the Ophiuchus Constellation, about 25,800 light-years from Earth. 

  • Singly-ionized germanium (Ge II) lines were detected for the first time in any EHe star, specifically in A980. 

  • Germanium in A980 was found to be eight times more abundant than in the Sun, indicating active stellar nucleosynthesis.