Spiral of a dying star

Wonderful photo isn't it? Again the Hubble Space Telescope shows us an incredible photo. And no, we are not interested in the star that is visible here, but in the faint spiral at the left of the star.

The spiral is made from material ejected by a red giant star, a star that is at the end of its life cycle. It has already burnt all its hydrogen, transformed it through nuclear fusion into helium , and it is now transforming helium into carbon, again through a process of nuclear fusion.

The spiral is due to the fact that the red giant star has a companion, another star, and the gravitational influence of the companion star "pushes" the material into a spiral.

Another very interesting fact is that the spiral is being lit, not by the binary star, but by galactic starlight!

More on the Hubble photograph here: An Extraordinary Celestial Spiral
The short scientific article is here, free for download: A Binary-Induced Pinwheel Outflow from the Extreme Carbon Star, AFGL 3068