Exploring a Metal-Deficient Helium Extreme Star with SALT Telescope

2024-04-18 16:14:07

Using the Southern African Large Telescope (SALT), astronomers led by Simon Jeffrey of Armagh Observatory, UK, have made high-resolution observations of a recently discovered helium extreme star (EC 19529−4430).

Related topics

It turns out that this star is the most metal-deficient among the group of known extreme helium stars.

This finding was reported in a paper published April 5 on the preprint website arXiv.

Extreme helium stars (EHe) are giants much larger and hotter than the Sun, but less massive and almost devoid of hydrogen, which is unusual, as hydrogen is the most abundant chemical element in the universe.

These stars are characterized by sharp, relatively strong lines of neutral helium, indicating low surface gravity and helium-dominated atmospheres.

In addition to helium, these stars also contain large amounts of carbon, nitrogen, and oxygen, and the first star was discovered in 1942.

The star (EC 19529−4430) is the youngest helium maximum star, located at a distance of about 15,500 light-years.

The new study revealed that it has an effective temperature of 20,700 Kelvin, and is composed primarily of helium treated with nitrogen and carbon (CNO), with excess nitrogen and a deficiency of carbon and oxygen.

The study confirms that it is the helium star that is poorest in metals. Researchers suggest that it was formed from the fusion of two white helium dwarfs in a binary system about 11 billion years ago, and it will develop into a dwarf after the combustion of helium.

Responsibility for the news: The Cedar News website is not responsible for this news, in form or content, and it only expresses the point of view of its source or writer.