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Nice question Andy. There are four mechanisms for the formation of smoke rings in general as opposed to in this image:
(1) The most common would be a cloud of gas and dust condenses under gravity, young stars start to form deep inside, and their radiation gradually blasts away a hollow cocoon. There are several examples of this in the image, including the base and body of the hooka, and one toward about 2 o'clock. A wonderful example is "Snoopy's beach ball" in Puppis.
(2) A supernova remnant. There would be no central star. The ring would be strong in SII and NII, which is a give-away. There's a lovely example in the Chalice Nebula which looks very like this.
(3) A Wolf-Rayett nebula. There would normally be a single very bright star in the centre. Given this image is of another galaxy, at extreme distance, this seems unlikely.
(4) A planetary nebula. The white dwarf would be a tiny dot visible in the centre. Again given this is in another galaxy, and planetary nebulas are tiny, that would be most unlikely.
If I had to take a guess, I'd guess a SNR, but I'd love to see the SII and NII images.
Best,
Mike
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