Central stars of planetary nebulae

In addition to studies of massive stars, some low and intermediate mass stars pass through a phase at the end of their (long) life when a 'planetary nebula' is being formed, in which late pulses remove surface hydrogen layers, revealing a spectrum reminiscent of massive stars.

A subset of these central stars of planetary nebulae (CSPN) exhibit a Wolf-Rayet spectrum. I have studied a variety of these with Orsola De Marco, for example SwSt1.

Although many examples of carbon-sequence Wolf-Rayet CSPNe are known, we have identified the first unambiguous example of a nitrogen-sequence CSPNe, IC4663. The image of IC4663 on this page shows a greyscale Gemini image ([OIII]) plus a colour HST composite (RGB = Halpha, [OIII], V-band).