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Black holes keep 'burping up' stars they destroyed years earlier, and astronomers don't know why
(www.livescience.com)
This is a most excellent place for technology news and articles.
I wonder if it could be caused by other celestial bodies captured in the black hole's orbit. Some new mass approaches the accretion disk and the gravitational pull slingshots some of the disk's matter out.
For the forces required to "pull" the matter out, we would need another singularity, but even then, that wouldn't show this.