Supersonic Cosmic Winds Collide in Rare Scene

A Chandra X-ray Observatory close-up on HD 5980 - the star (in yellow) is surrounded by the remnants of a supernova explosion (in red). Credits: NASA/CXC/ Nazé et al. CREDIT:

Two stellar titans are waging wars of wind in the first such scene spotted outside the Milky Way Galaxy.

The binary star system dubbed HD 5980 contains two stars weighing 30 and 50 times the mass of the Sun, each radiating more than a million times as much light as the Sun.

The photon pressure created from the outpouring of such blinding light carries gas from each star in a supersonic cosmic wind. These winds carry away an amount of mass each month equal to Earth, at a speed 5 times faster than the solar wind, said Ya?l Naze of the University of Li?ge in Belgium, lead scientist for the new study of the binary system.

The duo has a tight bond, separated by roughly 56 million miles (90 million kilometers), or about half the distance between the Earth and the Sun.

"These stars are so close to each other that if they were in our solar system they could fit inside the orbit of Venus," Naze said.

With such proximity, the winds smash into each other with titanic force, heating the gas to millions of degrees. The result is an X-ray light show for astronomers.

"The system emits about 10 times more energy in X-rays alone than the Sun radiates over the entire spectrum," said study team member Michael Corcoran of NASA's Goddard Space Flight Center in Greenbelt, Md.

Astronomers have identified similar X-rays from about two dozen similar systems in the Milky Way, but HD 5980's fireworks are the first to be spotted outside our galaxy.

An international team led by Naze spotted the system in the Small Magellanic Cloud--a galaxy located about 170,000 light-years from Earth. The astronomers relied on the European Space Agency's XMM-Newton X-ray Observatory and NASA's Chandra X-ray Observatory.

"It's interesting to be able to study an extragalactic colliding-wind binary like HD 5980 as if it were in our own galaxy," Corcoran said.

The two stars [image] are in the process of dying and eventually will explode as supernovae. Currently, the more massive star, HD 5980A, has begun an erratic stage within its life cycle called the Luminous Blue Variable (LBV) phase, which only occurs in the most massive of stars. Its stellar pal, HD 5980B, is an evolved Wolf-Rayet star that has already shed much of its original envelope.

• Vote: The Most Amazing Galactic Images Ever
• Video: Supernovas: Beacons in the Night
• Video: Supernovas: Destroyer/Creator
• Images: Amazing Galaxies
• Top 10 Star Mysteries