  We conducted a target of opportunity X-ray observation of the classical nova
V458 Vulpeculae 88 days after the explosion using the Suzaku satellite. With a
20 ks exposure, the X-ray Imaging Spectrometer detected X-ray emission
significantly harder than typical super-soft source emission. The X-ray
spectrum shows K lines from N, Ne, Mg, Si, and S, and L-series emission from Fe
in highly ionized states. The spectrum can be described by a single temperature
(0.64 keV) thin thermal plasma model in collisional equilibrium with a
hydrogen-equivalent extinction column density of ~3e21/cm2, a flux of ~1e-12
erg/s/cm2, and a luminosity of ~6e34 erg/s in the 0.3-3.0 keV band at an
assumed distance of 13 kpc. We found a hint of an enhancement of N and
deficiencies of O and Fe relative to other metals. The observed X-ray
properties can be interpreted as the emission arising from shocks of ejecta
from an ONe-type nova.
