Butterfly shaped nebulae with "varied histories and properties" are mysteriously aligned.
Nebulae are formed when a dying Sun-like star "puffs out" its layers into surrounding space, they often form eerie yet breathtaking shapes, a European Space Agency press release reported.
Although these nebulae don't interact with each other or their parent stars and have different characteristics, they all align the same way in the sky.
"This really is a surprising find and, if it holds true, a very important one," Bryan Rees of the University of Manchester, co-author of the paper, said. "Many of these ghostly butterflies appear to have their long axes aligned along the plane of our galaxy. By using images from both Hubble and the NTT we could get a really good view of these objects, so we could study them in great detail."
The astronomers made the discovery using NASA/ESA's Hubble Telescope and ESO's New Technology Telescope to observe about 130 planetary nebulae "in the bulge of our galaxy." The team found three different classifications of the heavenly objects.
"While two of these populations were completely randomly aligned in the sky, as expected, we found that the third - the bipolar nebulae - showed a surprising preference for a particular alignment," co-authorAlbert Zijlstra, also of the University of Manchester, said. "While any alignment at all is a surprise, to have it in the crowded central region of the galaxy is even more unexpected."
Bipolar nebulae have a "butterfly shape," and are believed to be created by jets blowing the mass away from the star system.
"The alignment we're seeing for these bipolar nebulae indicates something bizarre about star systems within the central bulge," Rees said. "For them to line up in the way we see, the star systems that formed these nebulae would have to be rotating perpendicular to the interstellar clouds from which they formed, which is very strange."
The properties of the nebulae's parent stars do contribute to their shape, but this research suggests there is another force at work. The finding also suggests the galactic "bulge" may have more of an influence on surrounding objects than previously believed.
