Planetary nebulae (maybe the most well-known of which, is the butterfly nebula) are some of the most magnificent structures you will find in the cosmos. They are formed when a medium-mass star comes to the end of its lifespan and begins to expel vast amounts of material into space. The hot core left behind, which is set to become a white dwarf in its near future, radiates strongly, and this pushes the shells of gas outwards into a cocoon-like shape. Often times, the remnants are spherical, but many of the ones that catch our eyes are remarkably complicated, comprised by series of knots, filaments, jets and layers. However, the cause of these mystical shapes was unknown until ESO turned the VLT to this region situated in the southern constellation of Centaurus.
Fleming 1 (as seen above) is best known for the striking S-shaped jets shooting out its poles. The ESO’s study set to investigate it. By examining the light from the center of the nebula, they deduced that there is likely not just one, but two white dwarfs in a 1.2 day orbit around each other. Their claim was backed up by the discovery of a ring of material within the structure, an obvious sign that this is a binary system. Because of the nature of medium-sized stars and their violent ending, finding two white dwarfs so close to one another is an incredibly rare find for astronomers.
So how has this strange system resulted in what we see today? Well, as the stars began to expand, one acquired a type of stellar vampirism, resulting in an accretion disk accumulating around it. The effect of both orbiting stars meant the disk acted like a spinning top – or the motion of precession. This motion affects any material that is fired outwards from the nebula; and in the case of Fleming 1, its jets. What is left is almost unbelievable symmetry, as you can see in the image!
The study has now confirmed that the process of precession between binary stars is, in fact, what is causing the stunningly symmetrical patterns around planetary nebulae such as Fleming 1 — more success for modern-day astronomy.
How Fleming 1 Measures Up: