  Stars falling too close to massive black holes in the centres of galaxies can
be torn apart by the strong tidal forces. Simulating the subsequent feeding of
the black hole with disrupted material has proved challenging because of the
range of timescales involved. Here we report a set of simulations that capture
the relativistic disruption of the star, followed by one year of evolution of
the returning debris stream. These reveal the formation of an expanding
asymmetric bubble of material extending to hundreds of astronomical units -- an
outflowing Eddington envelope with an optically thick inner region. Such
envelopes have been hypothesised as the reprocessing layer needed to explain
optical/UV emission in tidal disruption events, but never produced
self-consistently in a simulation. Our model broadly matches the observed light
curves with low temperatures, faint luminosities, and line widths of
10,000--20,000 km/s.
