We've Finally Found Our Sun's Long-Lost Sister

For the first time ever, astronomers have identified a star that emerged from the same cloud of dust and gas as our own. Intriguingly, there's a "small, but not zero" chance that our sister sun hosts planets hospitable to life.

For those of you who have been watching the rebooted Cosmos series, this announcement couldn't have been more timely. As Neil deGrasse Tyson just noted in a recent episode, our sun, along with others, formed in a massive cloud of dust and gas called a nebula. Consequently, it must have so-called "stellar siblings" floating around somewhere relatively near, but to date none have ever been found. Well, until now.


Chemical and Orbital Analysis

The star, HD 162826, was identified by Ivan Ramirez and his team at the University of Texas at Austin. It's located 110 light-years away in the constellation Hercules, is about 15% more massive than our sun, and is not visible to the naked eye.

Ramirez's team was able to match this star to our own by following up on 30 possible candidates. The astronomers used high-resolution spectroscopy to get a better understanding of the chemical make-up of these stars. In addition, they analyzed the orbits of these candidates, namely where they have been and where they are going in the paths around the center of the Milky Way.


Both the chemical analysis and orbital calculations narrowed the field of candidates to just one: HD 162826.

Life on Sibling Planets?

This particular star, which has been studied for the better part of 15 years, does not appear to have any massive planets orbiting close to it (so-called hot jupiters). Nor does a Jupiter-like planet reside at the farthest reaches of this solar system. But studies to date have not ruled out the presence of smaller terrestrial planets. According to Ramirez, there is a chance, "small, but not zero," that these solar sibling stars could host planets that harbor life.


What's more, he speculates that when these stars were forming in the birth cluster, collisions could have knocked chunks off of planets, and these fragments could have traveled between solar systems — possibly bringing primitive life to Earth.

"So it could be argued that solar siblings are key candidates in the search for extraterrestrial life," Ramirez noted in a release.


The study is set to appear in an upcoming edition of the Astrophysical Journal, but you can read it here (pdf): "Elemental Abundances of Solar Sibling Candidates." Additional information via University of Texas.

Image: ESO/L. Calcada.

Share This Story

Get our newsletter