The IP EX Hya was observed with FUSE during both a lower and higher state - due to fluctuations with the orbital phase. The spectrum here was obtained in the low state in which the WD is possibly revealed and contributes a significant fraction of the FUV flux. The spectrum has a relativelty good S/N. There is a sharp hydrogen Lyman beta emission line due to air glow. C iii (977 & 1175) and the O vi doublet are characterized by a shallow absorption on top of a braoder emission. The oxygen doublet also exhibits a narrow emission slightly red shifted. The atomic hydrogen and oxygen narrow absorption lines are from the ISM, and so are the C ii (1036 & 1037) and nitrogen lines (though some of the nitrogen lines could be contamination from the terrestrial atmosphere). The system exhibits narrow absorption lines (broader than the ISM lines) of highly ionized species such as S vi (933, 944), P iv, P v, O vi, S iv, Si iv as well as lines of Si ii, Si iii, S iii, S ii, C ii, C iii and He ii. This indicates that there are several absorbing layers with different temperatures.

          Bibliography

FUSE Data

Synthetic Spectrum

Click to see larger version of the plot

Click to see larger version of the plot

These data and models were published in the paper:

Godon, P., Sion, E.M., Levay, K., Linnell, A.P., Szkody, P., Barrett, P.E., Hubeny, I., Blair, W.P. 2012, ApJS, in press

Notes on figures:

When a model is shown, the portions of the observed spectrum that have been masked before the spectral fit are in blue, while the rest of the observed spectrum is in red. The model fit is shown the solide line in black (or possibly white). If the model is a composite made of a disk model and a white dwarf model, then these are shown with the dashed- and dotted lines (respectively). Some models include the effect of quasi-molecular HI absorption features, these are labelled "Q-mol" in the spectrum.