The optical spectrum and light curve of EC13471–1258 shows that it is an eclipsing binary with an orbital period of 3 ^ { h } 37 ^ { m } comprising a DA white dwarf and a dMe dwarf .
Total eclipses of the white dwarf are observed lasting 14 min , with the partial phases lasting 54 s. On one occasion , two pre-eclipse dips were seen .
Timings of the eclipses over ten years show jitter of up to 12 s. Flares from the M dwarf are regularly observed .
The M dwarf also shows a large amplitude ellipsoidal modulation in the V band light curve .
The component stars emit almost equal amounts of light at 5500 Å .

HST STIS spectra show strong Lyman alpha absorption with weak metal lines of C I , II and Si II superimposed .
Model atmosphere analysis yielded an effective temperature of 14220 \pm 300 K and log g of 8.34 \pm 0.20 for the white dwarf with these errors strongly correlated .
Its metal abundance is 1/30th solar with an uncertainty of 0.5 dex , and it is rapidly rotating with { V _ { 1 } sin i = 400 \pm 100 } km s ^ { -1 } .
The white dwarf also shows radial velocity variations with a semi-amplitude of 138 \pm 10 km s ^ { -1 } .
The gravitational redshift of the white dwarf was measured : 62 km s ^ { -1 } .

From optical spectroscopy the spectral type of the M dwarf was found to be M3.5-M4 , its temperature 3100 \pm 75 K , its rotational velocity 140 \pm 10 km s ^ { -1 } , its radial velocity semi-amplitude 266 \pm 5 km s ^ { -1 } , its mean V - I colour 2.86 and its absolute V magnitude 11.82 .
Intriguingly , its metal abundance is normal solar .

The H \alpha emission line shows at least two distinct components , one of which is uniformly distributed around the centre of mass of the M dwarf and provided the estimate of the rotational velocity of the M dwarf .
The other arises from the other side of the binary centre of mass , well within the white dwarf Roche lobe .
This behaviour is confirmed by Doppler tomography which shows the presence of two distinct velocity components within the primary Roche lobe .
The interpretation of these features is uncertain .
Variations in strength of the components with binary phase can be attributed to optical thickness in the Balmer lines .
Similar behaviour is seen in the observations of the other Balmer emission lines , although with poorer signal-to-noise .
Flares in H \alpha were observed and are consistent with arising from the vicinity of the M dwarf .

Dynamical solutions for the binary are discussed and yield an inclination of 75.5 \pm 2.0 ^ { o } , a white dwarf mass and radius of 0.78 \pm 0.04 M _ { \odot } 
and 0.011 \pm 0.01 R _ { \odot } , and an M dwarf mass and radius of 0.43 \pm 0.04 
M _ { \odot } and 0.42 \pm 0.02 R _ { \odot } .
These parameters are consistent with the Wood ( 1995 ) mass-radius relation for white dwarfs and the Clemens et al .
( 1998 ) mass-radius relation for M dwarfs ; we argue that the M dwarf just fills its Roche lobe .
The radius of the white dwarf and the model fit imply a distance of 48 \pm 5 pc and an absolute V magnitude of 11.74 .

The rapid rotation of the white dwarf strongly suggests that the system has undergone mass transfer in the past , and implies that it is a hibernating cataclysmic variable .
The M dwarf shows the properties expected of secondaries in cataclysmic variables : chromospheric activity and angular momentum loss .