Bizarre Alignment of Planetary Nebulae Discovered by Hubble and NASA
NASA has employed the Hubble Space Telescope to capture the image of a particularly bizarre alignment of planetary nebulae. In fact, they've found that butterfly-shaped members of this cosmic family tend to create this strange alignment, which is a surprising result given their different histories and varied properties.
When a star like our sun begins to die, it begins to puff out its outer layers into the surrounding reaches of space. This causes objects like planetary nebulae to form in a wide range of beautiful and striking shapes. One type of nebulae is called the bipolar planetary nebulae, which create ghostly hourglass or butterfly shapes around their parent stars. While all of these nebulae form in different places and have different characteristics, though, the new study shows some surprising similarities between some of these nebulae.
In all, the astronomers examined 130 planetary nebulae in the Milky Way's central bulge. They identified three different types and looked closely at their characteristics and appearance. While two of the populations were completely randomly aligned in the sky, though, the bipolar nebulae showed a surprising preference for a particular alignment.
"This really is a surprising find and, if it holds true, a very important one," said Bryan Rees, one of the researchers, in a news release. "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."
Planetary nebulae are thought to be sculpted by the rotation of the star system from which they form. This is dependent on the properties of the system, which means that the blown "bubble" is shaped by whether or not the system has planets or whether or not the system is binary.
"The alignment we're seeing for these bipolar nebulae indicates something bizarre about star systems within the central bulge," said Rees in a news release. "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 findings reveal a little bit more about these nebulae, and show exactly how odd they can be. It's possible that the central bulge that rotates around the galactic center may have greater influence than previously thought over our entire galaxy via its magnetic fields. For now, though, the astronomers plan to continue studying these nebulae.
The findings are published in the journal Monthly Notices of the Royal Astronomical Society.