Astronomy

Choose the Correct Answer

Correct Answer : Option b

Explanation
Recently, astronomers from the Indian Institute of Astrophysics (IIA), an autonomous institute of the Department of Science and Technology (DST) found Extreme Helium (EHe) stars using the Hanle Echelle Spectrograph on the Himalayan Chandra Telescope in Ladakh.

Statement 1 is correct: Extreme Helium (EHe) stars are very rare and unusual because they have almost no hydrogen, unlike most stars such as our Sun, which are mainly made of hydrogen. Even though these stars do not have much mass compared to typical supergiants, they are called supergiants because they are very bright and have a large size.

Statement 2 is not correct: Extreme Helium (EHe) stars are not formed by the direct collapse of gas clouds in space. Instead, the study proposes that Extreme Helium (EHe) could be the result of a merger between a helium white dwarf and a carbon-oxygen white dwarf—an event dramatic enough to stir up and distribute these rare elements.

Statement 3 is correct: Extreme Helium (EHe) stars are very rare stars that are made mainly of helium, with heavier elements like carbon as the next most common element, and sometimes contain nitrogen and oxygen as well. Unlike most stars, which are mostly composed of hydrogen, Extreme Helium (EHe) stars have almost no hydrogen in their composition.