Twin Star Insights Into Sun's Future
August 28, 2013

New Solar Twin Provides Insight Into Our Sun’s Future

[ Watch the Video: The Life Cycle of a Sun-Like Star ]

Lee Rannals for - Your Universe Online

Astronomers have identified what they are calling the Sun's oldest twin, HIP 102152, sitting 250 light-years away from us. A team of astronomers using the European Southern Observatory's (ESO) Very Large Telescope (VLT) found that HIP 102152 is older but otherwise nearly identical to our Sun, giving astronomers a chance to see how our local star will look as it ages.

Our Sun is about 4.6 billion years old, but astronomers have only been observing it with telescopes for about 400 years. In order to get a better picture of how our star ages, scientists must look outside our solar system and observe others. The latest find allows astronomers to look about 4 billion years into the future of our sun.

"We have now obtained superb-quality spectra from the VLT and can scrutinize solar twins with extreme precision, to answer the question of whether the Sun is special," Jorge Melendez, the leader of the team and co-author of the new paper published in Astrophysical Journal Letters, said in a press release.

HIP 102152 is estimated to be about 8.2 billion years old, or 3.6 billion years older than the Sun. So far, the team already has made at least one key discovery about the future of our star. Namely, the new observations help provide the first clear link between a star's age and its lithium content.

Lithium, the third element on the periodic table, has puzzled scientists observing stars. Astronomers have noticed that some stars appear to have less lithium than others, and the latest observations may give hints as to why.

“We have found that HIP 102152 has very low levels of lithium," TalaWanda Monroe, the lead author on the new paper, said in a statement. "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 sun has just one percent of the lithium content that it had when it first formed. Younger solar twins have been seen to have significantly larger amounts of lithium, and the latest observations show a clear connection between a star's age and its lithium content.

In May scientists reported that they discovered another older solar twin that is approximately 6.7 billion years old. This research shows that it won't take 4 billion years for the sun to outgrow us. According to these findings, in two billion years our sun's radiation may increase and make the Earth's surface so hot that liquid water can no longer exist in its natural state.