“Is the solar-system sized bubble in the Consellation Cygnus a planetary nebulae or could it be an “AC” or astroengineering construction, also known as a Dyson sphere, named after Freeman Dyson of the Princeton Institute for Advanced Study who proposed the theory?”
No it could not, for two reasons.
First, it’s transparent (you can see stars through most of it), hence it is not absorbing the central star’s radiation and re-radiating in the infrared.
Second, Dyson spheres have been shown to be unstable over time, the central star’s gravity would cause it to collapse or at least impact the star.
Even a “ringworld” type construct would require active stabilization.
I’m pretty sure I read something from Dyson himself that he had been mis-understood by sci-fi writers into thinking that he had meant a solid spherical structure whereas he had actually meant more of a swarm of habitats that would orbit indepentently and absorb the energy from their star.
My sci fi roomie made the transparency argument. However, is it possible that a civilization could create a dust veil bubble as an interstellar signal which would allow stars to shine through. I would like to ask my friend, but he said, “be quiet, I am studying the market” ;-)
Also, since you seem pretty knowledgeable, what do you think it might be?