SIMBAD references

Eight planetary nebulae have been identified as 'born-again', a class of object typified by knotty secondary ejecta having low masses (∼10^–4 M_☉) with nearly no hydrogen. Abell 30, the archetype of the class, also belongs to a small subset of planetary nebulae that exhibit extreme abundance discrepancy factors (where Abell 30 is the most extreme), a phenomenon strongly linked to binary star interactions. We report the presence of light curve brightness variations having a period of 1.060 d that are highly suggestive of a binary central star in Abell 30. If confirmed, this detection supports the proposed link between binary central stars and extreme abundance discrepancies.