How was this strange structure formed?
The Blue Ring Nebula is home to a central star, known as TYC 2597-735-1. An unusual ultraviolet ring surrounds the star, which astronomers first observed in 2004 using NASA’s now-defunct Galaxy Evolution Explorer (GALEX) space telescope. We didn’t know what it was. Up to now.
“Every time we thought we had solved this, something would tell us, ‘No, that’s not right,'” says Mark Seibert, an astrophysicist at the Carnegie Institution for Science. “This is a terrifying thing as a scientist. But I also love how unique this object is and the effort so many people go to discovering it.”
Thus, using the WM Keck Observatory in Hawaii, scientists have discovered that the blue ring is actually the base of a cone-shaped cloud of bright molecular hydrogen that extends from the central star towards Earth . They have also observed a second cone-shaped cloud extending from the star in the opposite direction.
These cone-shaped clouds appear to overlap when viewed from Earth, creating the ring shape around the star, experts clarify in their study published in the journal Nature .
The most recent example of the merger of two stars
Researchers believe that fluorescent debris clouds formed after a Sun-like star collided and consumed a smaller star only a few thousand years ago. This collision ejected a hot debris cloud into space that created a shock wave that, in turn, heated the hydrogen molecules in the debris cloud, producing the ultraviolet emissions that scientists first observed in 2004.
Reference: Keri Hoadley, D. Christopher Martin, Brian D. Metzger, Mark Seibert, Andrew McWilliam, Ken J. Shen, James D. Neill, Gudmundur Stefansson, Andrew Monson, Bradley E. Schaefer. A blue ring nebula from a stellar merger several thousand years ago. Nature, 2020; 587 (7834): 387 DOI: 10.1038 / s41586-020-2893-5
