NASA Hubble (HST) Image: Doradus Nebula and the Runaway Star

This image of the 30 Doradus nebula, a rambunctious stellar nursery, and the enlarged inset photo show a heavyweight star that may have been kicked out of its home by a pair of heftier siblings.

In the inset image at right, an arrow points to the stellar runaway and a dashed arrow to its presumed direction of motion.

Credit for Hubble Image: NASA, ESA, J. Walsh (ST-ECF), and ESO Acknowledgment: Processing by Z. Levay (STScI) Credit for wide-field Image: ESO Acknowledgement: J. Alves (Calar Alto, Spain), and B. Vandame and Y. Beletski (ESO). Processing by B. Fosbury (ST-ECF).

A heavy runaway star is rushing away from a nearby stellar nursery at more than 250,000 miles an hour, a speed that will get you to the Moon and back in two hours. The runaway is the most extreme case of a very massive star that has been kicked out of its home by a group of even heftier siblings.

The homeless star is on the outskirts of the 30 Doradus nebula, a raucous stellar breeding ground in the nearby Large Magellanic Cloud.

The finding bolsters evidence that the most massive stars in the local universe reside in 30 Doradus, making it a unique laboratory for studying heavyweight stars. Also called the Tarantula Nebula, 30 Doradus is roughly 170,000 light-years from Earth.

Tantalising clues from three observatories, including the Hubble Space Telescope's newly installed Cosmic Origins Spectrograph (COS), and some old- fashioned detective work, suggest that the star may have traveled about 375 light-years from its suspected home, a giant star cluster called R136. Nestled in the core of 30 Doradus, R136 contains several stars topping 100 solar masses each.

The observations offer insights into how massive star clusters behave.

"These results are of great interest because such dynamical processes in very dense, massive clusters have been predicted theoretically for some time, but this is the first direct observation of the process in such a region," says Nolan Walborn of the Space Telescope Science Institute in Baltimore and a member of the COS team that observed the misfit star.

"Less massive runaway stars from the much smaller Orion Nebula Cluster were first found over half a century ago, but this is the first potential confirmation of more recent predictions applying to the most massive young clusters."