  We present a Chandra observation of the exceptional planet bearing A5V star
HR 8799, more precisely classified as a kA5hF0mA5 star and search for intrinsic
X-ray emission. We clearly detect HR 8799 at soft X-ray energies with the
ACIS-S detector in a 10 ks exposure; minor X-ray brightness variability is
present during the observation. The coronal plasma is described well by a model
with a temperature of around 3 MK and an X-ray luminosity of about Lx = 1.3 x
10^28 erg/s in the 0.2-2.0 keV band, corresponding to an activity level of log
Lx/Lbol ~ -6.2. Altogether, these findings point to a rather weakly active and
given a RASS detection, long-term stable X-ray emitting star. The X-ray
emission from HR 8799 resembles those of a late A/early F-type stars, in
agreement with its classification from hydrogen lines and effective temperature
determination and thus resolving the apparent discrepancy with the standard
picture of magnetic activity that predicts mid A-type stars to be virtually
X-ray dark.
