I present pointed ROSAT PSPC observations of the pre-cataclysmic binary V471 Tauri .
The hard X-ray emission ( > 0.4 keV ) is not eclipsed by the K star , demonstrating conclusively that this component can not be emitted by the white dwarf .
Instead I show that its spectrum and luminosity are consistent with coronal emission from the tidally spun-up K star .
The star is more active than other K stars in the Hyades , but equally active as K stars in the Pleiades with the same rotation periods , demonstrating that rotation—and not age—is the key parameter in determining the level of stellar activity .

Ths soft X-ray emission ( < 0.4 keV ) is emitted predominately by the white dwarf and is modulated on its spin period .
I find that the pulse-profile is stable on timescales of hours and years , supporting the idea that it is caused by opacity of accreted material .
The profile itself shows that the magnetic field configuration of the white dwarf is dipolar and that the magnetic axis passes through the centre of the star .

There is an absorption feature in the lightcurve of the white dwarf , which occurs at a time when our line-of-sight passes within a stellar radius of the K star .
The column density and duration of this feature imply a volume and mass for the absorber which are similiar to those of coronal mass ejections of the Sun .

Finally I suggest that the spin-orbit beat period detected in the optical by Clemens et al . may be the result of the interaction of the K-star wind with the magnetic field of the white dwarf .