Artist's impression of a pair of stars at the start of a common envelope phase
![](https://mb.cision.com/Public/5569/3472817/a3a29cc1cde129c6_800x800ar.jpg)
Photographer: Danielle Futselaar, artsource.nl
A pair of stars at the start of a common envelope phase. In this artist's impression, we get a view from very close to a binary system in which two stars have just started to share the same atmosphere. The bigger star, a red giant star, has provided a huge, cool, atmosphere which only just holds together. The smaller star orbits ever faster round the stars' centre of mass, spinning on its own axis and interacting in dramatic fashion with its new surroundings. the interaction creates powerful jets that throw out gas from its poles, and a slower-moving ring of material at its equator.