Astronomers Discover Sun's Oldest Solar Twin: Star Reveals Future

Our sun may have a solar twin--in a manner of speaking. Astronomers have used ESO's Very Large Telescope to study a star that is more like our sun than any other to date-except for the fact that it's about four billion years older. The findings could reveal a bit more about the future of our own parent star.

The star is named HIP 102152 and is located about 250 light-years from Earth in the constellation of Capricornus. Yet it wasn't the only one that the researchers took a look at. They also examined 18 Scorpii, a solar twin that they thought to be younger than our sun. This allowed the scientists to get a view of two different stages of "life" that our sun might have gone and might go through.

The scientists used the UVES spectrograph on the VLT in order to split up the stars' light into its component chemicals. This allowed the researchers to study the chemical composition and other properties of the two stars in great detail.

It turns out that HIP 102152 is about 8.2 billion years old, compared to the 4.6 billion years for our own sun. In contrast, 18 Scorpii was a mere 2.9 billion years old. In addition, the researchers discovered what the lithium content was for these two different stars.

Some stars have less lithium than others, a fact that has puzzled scientists for years. Yet by examining these two stars, the researchers may have pinned down why this is. It's possible that the older a star becomes, the less lithium it contains.

"We have found that HIP 102152 has very low levels of lithium," said TalaWanda Monroe, one of the researchers, in a news release. "This demonstrates clearly for the first time that older solar twins do indeed have less lithium than our own Sun or younger solar twins. We can now be certain that stars somehow destroy their lithium as they age, and that the Sun's lithium content appears to be normal for its age."

The findings reveal what our own sun may look like in the future and what our nearest star may have looked like in the past. In addition, the research shows that HP 102152 may host rocky planets, which could pave the way for future studies.

The new study is published in the journal Astrophysical Journal Letters.