This colorful cosmic gas cloud testifies to the dramatic outcome of a stellar conflict. Because here two stars came so close that the larger one swallowed the smaller one. Its spiraling movements created the complex patterns in the ejected gas clouds.
Stars also go through a life cycle and age. When they have used up all the hydrogen inside them in the nuclear fusion, they gradually swell to a red giant – in this state our sun will reach Earth’s orbit. After a while this state also becomes unstable and the dying star throws its outer shells out into space. These gases form luminous, often colorful clouds – a so-called planetary nebula.
This image of the Atacama Large Millimeter / Submillimeter Array (ALMA) is also such a gas cloud. But it has an unusual story: “The star system HD101584 is something special in that this ‘dying process’ was ended prematurely and dramatically,” explains Hans Olofsson from Chalmers University in Sweden. Because this complex gas cloud testifies to the “fight” between two nearby stars.
When the main star swelled to a red giant, it grew large enough to swallow its lesser-mass partner. In response, the smaller star spiraled toward the giant’s core but did not collide with it. Instead, his maneuver caused the larger star to erupt prematurely, dramatically dispersing its gas layers and exposing its core. In addition, rapid gas fountains formed, which shot through the previously ejected material and formed the gas rings and the bright bluish and reddish spots in the fog.
“With detailed images of the surroundings of HD101584, we can make the connection between the giant star that it was before and the stellar remnant that it will soon become,” says Sofia Ramstedt from Uppsala University. In the near future the Extremely Large Telescope of the European Southern Observatory will show what it looks like in the heart of this gas cloud. This is currently being built in the Chilean Atacama Desert.