Unique star discovered that challenges previous understanding of star formation processes

Source: The post is based on the article “Unique star discovered that challenges previous understanding of star formation processes”  published in Department of Science and Technology’s website.

What is the News?

Scientists at the Indian Institute of Astrophysics (IIA, Bangalore) have discovered a unique star named HE 1005-1439.This star has been classified as a carbon-enhanced metal-poor (CEMP) star.

What are Carbon-enhanced metal-poor (CEMP) Stars?

CEMP Stars are primarily characterized by diverse heavy elements and abundance patterns. They were formed from the ejected material of the first stars that formed after the Big Bang.

These stars are primarily classified into four groups, based on which groups of heavy elements are more abundant. These are mostly dwarf stars, subgiant stars or giant stars.

At the evolutionary stages in which the stars exist, they are not expected to produce heavy elements. 

However, the surface chemical composition of these stars exhibit abundances of heavy elements those are about 100 to 1000 times higher than that of the Sun. 

What is HE 1005-1439?

HE 1005-1439 is classified as a carbon-enhanced metal-poor (CEMP) star.This star challenges previous ideas about star formation. 

This star shows signs of being formed through a combination of two different processes called neutron-capture processes – the slow (s-) process and the intermediate (i-) process. 

The iron content of the star is thousand times less than that of the sun and it is heavily enriched with neutron-capture elements.

Significance: This is the first time scientists have come across an object with a surface chemical composition that exhibits contributions from both slow(s) and intermediate (i) neutron-capture nucleosynthesis. The observed abundance pattern is quite unique and has never been observed before in any CEMP stars.