Narayan, Ramesh2019-09-222004Narayan, Ramesh. 2004. “Black Hole Event Horizon.” Progress of Theoretical Physics Supplement 155: 263–70. https://doi.org/10.1143/ptps.155.263.0375-9687http://nrs.harvard.edu/urn-3:HUL.InstRepos:41384892Type I X-ray bursts are frequently observed in neutron star X-ray binaries, but no Type I burst has ever been seen in any black hole X-ray binary. It is argued that the lack of bursts in the latter sources is strong evidence that the accreting stars have event horizons.en-USJournal Article2019-09-2210.1143/PTPS.155.263