Planetary Nebulae are a transitory phase in the evolution of low/intermediate mass stars (note they have nothing to do with real planets!). They are formed when the outer envelope of an evolved red supergiant is ejected and then photoionised by the now exposed, and very hot, stellar core.

Understanding the shaping of these objects has been difficult. While spherical objects are understandable, most objects are actually elliptical or bipolar in shape. At QUB we are trying to assess how important binarity is to nebula shaping using a variety of techniques.

Some central stars can become unstable as they approach the white dwarf regime. In an explosive event they can undergo a thermal pulse and be reborn as red supergiant stars. Subsequently they eject nebular material and evolve through a second Planetary Nebula phase. Well thats the theory, in practice, objects that undergo this evolution are rarely seen. However recently we have been fortunate to discover one event and QUB astronomers are trying to understand its rapid evolution.

Nebula are natural laboratories in which to test our physics knowledge. The low density conditions favour atomic transitions that are difficult, if not impossible, to reproduce on earth. Hence we can use these objects to test and clarify our atomic physics calculations and also use this information to understand the constitution of difference galaxies hence restricting models of their formation.