Can mixed star-plus-wormhole systems mimic black holes?
  We consider mixed strongly gravitating configurations consisting of a wormhole threaded by two types of ordinary matter. For such systems, the possibility of obtaining static spherically symmetric solutions describing compact massive central objects enclosed by high-redshift surfaces (black-hole-like configurations) is studied. Using the standard thin accretion disk model, we exhibit potentially observable differences allowing to distinguish the mixed systems from ordinary black holes with the same masses. 
Vladimir Dzhunushaliev, Vladimir Folomeev, Burkhard Kleihaus, Jutta   Kunz
gr-qc astro-ph.SR