College of LAS « Illinois

Astronomy

The Sun Has Siblings?

Fields and Looney

Our Sun may not be an only child after all.

Astronomers in the College of LAS have found evidence that the Sun may have hundreds or thousands of celestial siblings, now dispersed across the heavens.

Astronomers Leslie W. Looney and Brian D. Fields, along with undergraduate student John Tobin, found this evidence while studying short-lived radioactive isotopes, which are created when massive stars end their lives in spectacular explosions called supernovas. Some of these radioactive isotopes mixed with material that formed meteorites and then fell to the Earth.

These radioisotopes left their signature in what are called “daughter species.” By studying the daughter species, Looney and Fields deduced that the supernova, which created these radioisotopes, was “stunningly close” to the early Sun.

What’s more, wherever there are supernovas, you also find star clusters—hundreds to thousands of stars. Therefore, it’s likely that our Sun was born in such a cluster. But because the stars were not gravitationally bound to one another, the Sun’s siblings wandered away millennia ago. The siblings were lost in space.

Winter 2008