While taking a look at more than a hundred planetary nebulae in our galaxy’s central bulge, astronomers using the NASA/ESA Hubble Space Telescope and ESO’s New Technology Telescope have found something rather incredible. It would appear that butterfly-shaped planetary nebulae – despite their differences – are somehow mysteriously aligned!
We know that stars similar to our Sun end their lives shedding their outer layers into space. Like a reptile’s intact skin casing, this stellar material forms a huge variety of shapes known as planetary nebulae. One of the more common forms is bipolar – which creates a bowtie or butterfly shape around the progenitor star.
Like snowflakes, no two planetary nebulae are exactly alike. They are created in different places, under different circumstances and have very different characteristics. There is no way that any of these nebulae, nor the responsible stars that formed them, could have interacted with other planetary nebulae. However, according to a new study done by astronomers from the University of Manchester, UK, there seems to be a rather incredible coincidence… A surprising number of these stellar shells are lining up the same way from our galactic point of view.
“This really is a surprising find and, if it holds true, a very important one,” explains Bryan Rees of the University of Manchester, one of the paper’s two authors. “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 term planetary nebulae is odd, since these are phenomena of stars, not planets.
The term “planetary nebula” is arguably a misnomer, since this phenomenon is not associated with observations of actual planets, and perhaps was derived from the planet-like round shape of these nebulae as observed by astronomers through early telescopes.