We find that the classical nova V723 Cas ( 1995 ) is still an active X-ray source more than 12 years after outburst and analyze seven X-ray observations carried out with Swift between 2006 January 31 and 2007 December 3 .
The average count rate is 0.022 \pm 0.01 cts s ^ { -1 } but the source is variable within a factor of two of the mean and does not show any signs of turning off .
We present supporting optical observations which show that between 2001 and 2006 an underlying hot source was present with steadily increasing temperature .
In order to confirm that the X-ray emission is from V723 Cas , we extract a ROSAT observation taken in 1990 and find that there was no X-ray source at the position of the nova .
The Swift XRT spectra resemble those of the Super Soft X-ray binary Sources ( SSS ) which is confirmed by RXTE survey data which show no X-ray emission above 2 keV between 1996 and 2007 .
Using blackbody fits we constrain the effective temperature to between T _ { eff } = ( 2.8 - 3.8 ) \times 10 ^ { 5 } K and a bolometric luminosity \gtrsim 5 \times 10 ^ { 36 } erg s ^ { -1 } and caution that luminosities from blackbodies are generally overestimated and temperatures underestimated .
We discuss a number of possible explanations for the continuing X-ray activity , including the intriguing possibility of steady hydrogen burning due to renewed accretion .