A pair of researchers from the Observatories of the Carnegie Institution for Science and the California Institute of Technology have reported evidence that some super-puff exoplanets might be ringed exoplanets. Anthony Piro and Shreyas Vissapragada have written a paper describing their theory and the evidence supporting it and have posted it on the arXiv preprint server.
Source:
https://phys.org/news/2019-12-evidence-super-puffs-exoplanets.html