November 21, 2011

Runaway Stars May Be Fleeing Bigger Bullies

A class of wandering stars called OB runaways may have been thrown from home by competing binary star systems that got too close. John Matson reports

SUBSCRIBE TO 60-Second Space

Apple | Spotify | RSS

Join Our Community of Science Lovers!

Back in the 1950s astronomers discovered a strange population of stars on the lam. Known as OB runaways, these massive stars tear through space at surprisingly high speed—sometimes hundreds of kilometers per second.

How they got going so fast is an open question. It's been proposed that other, exploding stars could be the reason. A supernova, after all, packs enough punch to launch a neighboring star outward at high speed. But a new study published online by the journal Science supports an alternative idea. [Michiko S. Fujii and Simon Portegies Zwart, "The Origin of OB Runaway Stars"]

The mechanism involves a bully binary—that's the astronomers' actual language. The bully is a pair of supersize stars orbiting each other within a larger star cluster. If a third star ventures too close, the bully binary flings it clear like a slingshot. Voila! A runaway. According to the new study, bully binaries form naturally and can each fling out dozens of runaways. And the number of massive stars ejected this way matches up well with actual observations of OB runaways.

On supporting science journalism

If you're enjoying this article, consider supporting our award-winning journalism by subscribing. By purchasing a subscription you are helping to ensure the future of impactful stories about the discoveries and ideas shaping our world today.

So who can blame the runaway stars for fleeing an unfair fight? As it's been said: "Discretion is the better part of valor."

—John Matson

[The above text is a transcript of this podcast.]

It’s Time to Stand Up for Science

If you enjoyed this article, I’d like to ask for your support. Scientific American has served as an advocate for science and industry for 180 years, and right now may be the most critical moment in that two-century history.

I’ve been a Scientific American subscriber since I was 12 years old, and it helped shape the way I look at the world. SciAm always educates and delights me, and inspires a sense of awe for our vast, beautiful universe. I hope it does that for you, too.

If you subscribe to Scientific American, you help ensure that our coverage is centered on meaningful research and discovery; that we have the resources to report on the decisions that threaten labs across the U.S.; and that we support both budding and working scientists at a time when the value of science itself too often goes unrecognized.

In return, you get essential news, captivating podcasts, brilliant infographics, can't-miss newsletters, must-watch videos, challenging games, and the science world's best writing and reporting. You can even gift someone a subscription.

There has never been a more important time for us to stand up and show why science matters. I hope you’ll support us in that mission.

Thank you,

David M. Ewalt, Editor in Chief, Scientific American