Sgr A$^*$ envelope explosion and the young stars in the centre of the
  Milky Way
  Sgr A$^*$ is the super massive black hole residing in the centre of the Milky
Way. There is plenty of observational evidence that a massive gas cloud fell
into the central parsec of the Milky Way $\sim 6$ million years ago, triggering
formation of a disc of young stars and activating Sgr A$^*$. In addition to the
disc, there is an unexplained population of young stars on randomly oriented
orbits. Here we hypothesize that these young stars were formed by fragmentation
of a massive quasi-spherical gas shell driven out from Sgr A$^*$ potential well
by an energetic outflow. To account for the properties of the observed stars,
the shell must be more massive than $10^5$ Solar masses, be launched from
inside $\sim 0.01$~pc, and the feedback outflow has to be highly
super-Eddington albeit for a brief period of time, producing kinetic energy of
at least $10^{55}$~erg. The young stars in the central parsec of the Galaxy may
be a unique example of stars formed from atomic rather than molecular hydrogen,
and forged by extreme pressure of black hole outflows.
