ASTRONOMERS have detected one of the oldest stars in the universe and it dates back a staggering 13.5 billion years.

Scientists found the star by looking at its metal content which is the lowest of any star ever discovered.

The stellar body is only around 10 percent of the mass of the sun which is why it has gone undetected for so long despite being in the Milky Way.

The new star called 2MASS J18082002-5104378 B was formed very early on in the life of the universe when there were no metals.

Generally, the younger the star the higher its metal content.

“We’ve never discovered a star so low mass and made of so few grams of metals,” astrophysicist Andrew Casey of Monash University in Australia told ScienceAlert.

“This discovery tells us that the very first stars in the universe didn’t have to all be massive stars that died long ago.”

Experts believe the find shows that these tiny stars could in theory live for trillions of years.

It also forces astronomers to re-write the theory that old stars are all huge.

“These ancient stars could form from very small amounts of material, which means some of those relics from soon after the Big Bang could still exist today.

“These stars are extremely rare — it’s much like finding a needle among an acre of haystacks,” he said.

The star was found because it has a binary companion which astronomers happened to be studying at the time.

First-generation stars are objects formed in the early universe (within a few hundred million years after the Big Bang) from gas clouds containing only hydrogen and helium.

They are the probable precursors of the formation of the universe’s structure and chemical enrichment; large stellar systems, such as galaxies, formed later.

Dr. Casey believes the find could bring us closer to properly understanding how the first stars formed.

Their findings are due to be published in the Astrophysical Journal.

Earlier this year, astronomers detected the moment when the lights were first turned on in the universe.

Using a radio antenna not much larger than a refrigerator, researchers discovered signals from the first stars that formed after the Big Bang 13.8 billion years ago.

(SD-Agencies)