The Enigma Nebula and a new PN Candidate Discovery Lu4

After the integration to my surprise there was distinct OIII emission in the centre and on RGB images a distinct blue star was visible suggesting this may be a large uncatalogued planetary nebula. The candidate appears to have a faint outer shell to the East, and if this is confirmed, the major diameter would be 71.2 arc minutes, so it is a real giant and it may potentially be one of the largest known planetary nebulas! Unfortunately getting these new discoveries catalogued in the HASH database is now very difficult as a new object has to have a classic PN morphology. Pascal Le Dû and Professor Quentin Parker have reviewed my data but feel spectroscopic confirmation is required to confirm it as a new planetary nebula, and as such it has not been registered in the PlanetaryNebula.net and HASH databases.  Of course it may also turn out to not be a planetary nebula but may be an ionised HII region.

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After initially publishing my image, I received a number of messages about this object. It turns out Dana Patchick and Sakib Rasool looked at this object on survey data a few years ago but didn’t find a suitable central star. The StDr team of Marcel Drechsler and Xavier Strottner also examined it, and Bray Falls picked it up on a wide field image he took from his setup in Namibia, but like me, was unsuccessful in getting it registered in PN.net/HASH. Tim Schaffer and the NHZ team also found the object on a wide field image they took. It is a pretty awesome reflection on the amateur community that we had 5 groups who all independently found the object on survey and Bray and Tim/NHZ with their own data, when it has been overlooked by the pros for so long! Dana Patchick suspects the CSPN I identified is likely a sub white dwarf (likely an sd, sdO, or He-sdO) and looks close enough to create such as shell. White sub-dwarfs do have a track record of creating giants shells, with the massive PaStDr 9 having a He-sdO as its emitting source.

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In recognition of the amateur contribution to the object, we have all coordinated and the consensus was to refer to this object as the Enigma Nebula.

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In addition to the Enigma Nebula, there is a second smaller new PN candidate to the bottom right of the image, which has been accepted as a new discovery in PN.net and HASH catalogued as Ludgate 4/Lu4.. There are also a number of known smaller and brighter PN, MPA J1413-6709, LoTr9 and WRAY 16-150  which appear superimposed on the much larger nebula.