EXTREME HELIUM STAR (EHe)

June 22, 2020

A study by the Indian Institute of Astrophysics (IIA) which detected the presence of singly ionised fluorine for the first time in the atmospheres of hot Extreme Helium Stars makes a strong case that the main formation of these objects involves a merger of a carbon-oxygen (CO) and a Helium (He) white dwarf.

About:

  • An extreme helium star or EHe is a low-mass supergiant that is almost devoid of hydrogen, the most common chemical element of the universe.

  • There are 21 of them detected so far in our galaxy.

  • The origin and evolution of these Hydrogen deficient objects have been shrouded in mystery.

  • Since there are no known conditions where stars devoid of hydrogen can be formed from molecular clouds, it is theorized that they are the product of the mergers of helium-core and carbon-oxygen core white dwarfs. 

Source : PIB