Coronal radiation of a cusp of spun-up stars and the X-ray luminosity of
  Sgr A*
  Chandra has detected optically thin, thermal X-ray emission with a size of ~1
arcsec and luminosity ~10^33 erg/s from the direction of the Galactic
supermassive black hole (SMBH), Sgr A*. We suggest that a significant or even
dominant fraction of this signal may be produced by several thousand late-type
main-sequence stars that possibly hide in the central ~0.1 pc region of the
Galaxy. As a result of tidal spin-ups caused by close encounters with other
stars and stellar remnants, these stars should be rapidly rotating and hence
have hot coronae, emitting copious amounts of X-ray emission with temperatures
kT<~ a few keV. The Chandra data thus place an interesting upper limit on the
space density of (currently unobservable) low-mass main-sequence stars near Sgr
A*. This bound is close to and consistent with current constraints on the
central stellar cusp provided by infrared observations. If coronally active
stars do provide a significant fraction of the X-ray luminosity of Sgr A*, it
should be variable on hourly and daily time scales due to giant flares
occurring on different stars. Another consequence is that the quiescent X-ray
luminosity and accretion rate of the SMBH are yet lower than believed before.
