Context : Nova Eridani ( 2009 ) caught the eye of the nova community due to its fast decline from maximum , which was initially missed , and its subsequent development in the radio and X-ray wavelengths .
This system also exhibits properties similar to those of the much smaller class of recurrent novae ; themselves potential progenitors of Type Ia Supernovae .

Aims : We aim to determine the nature and physical parameters of the KTÂ Eri progenitor system .

Methods : We searched the Harvard College Observatory archive plates for the progenitor of KTÂ Eri to determine the nature of the system , particularly the evolutionary stage of the secondary .
We used the data obtained to search for any periodic signal and the derived luminosity to estimate a recurrence timescale .
Furthermore , by comparing the colours of the quiescent system on a colour-magnitude diagram we may infer the nature of the secondary star .

Results : We identified the progenitor system of KTÂ Eri and measured a quiescent magnitude of < B > = 14.7 \pm 0.4 .
No previous outburst was found .
However , we suggest that if the nova is recurrent it should be on a timescale of centuries .
We find a periodicity at quiescence of 737 days which may arise from reflection effects and/or eclipses in the central binary .
The periodicity and the quiescence magnitude of the system suggest that the secondary star is evolved and likely in , or ascending , the Red Giant Branch .
A second period is evident at 376 days which has a sinusoidal like light curve .
Furthermore , the outburst amplitude of \sim 9 magnitudes is inconsistent with those expected for fast classical novae ( \sim 17 magnitudes ) which may lend further support for an evolved secondary .

Conclusions : We investigated the probable recurrent nova KT Eri for which we suggest an inter-outburst period of order centuries and an evolved secondary .
This may suggest that there is a whole range of possible inter-outburst periods in between the “ typical ” classical and recurrent novae nomenclature .
Archival searches are an excellent tool in order to investigate the nature of astrophysical objects , in order to determine the nature and physical parameters .