APOD: The Ghost of Jupiter's Halo (2019 Jul 11)

[JohnD]

Are the 'beams' shining around the nebula real, or just artefacts like the diffraction spikes that appear over stars?

They are real... that is, they are not optical artifacts like diffraction spikes. Whether they are "beams" is a different question (or perhaps the question is "what is a beam?"). What we're seeing could be actual linear concentrations of material, but it could also be preferentially illuminated material, if the stimulating light source is partly occluded (as by dust), resulting in non-uniform illumination of an otherwise fairly homogeneous medium.

Thank you Chris! There is an intensification of the halo, at 6 o'clock, with a 'beam' either side of it, so I see what you mean. Light could be shining either side of that to show up gas ejected even earlier from the object.

JOhn