This FUSE spectrum is rather noisy and is heavily affected by ISM absorption lines from atomic and molecular hydrogen, as well as from metals (Ar i, Fe ii, S i, N i). The C iii (977 & 1175) and oxygen doublet lines are in broad emission with a narrower absorption feature superposed to them. We identify absorption lines from N iv (923), S vi (933, 944), oxygen doublet, and C iii (1175) which are all slightly red shifted (by about 1A), an indication that they possibly do not belong to the WD photosphere per se. We do, however, identify some absorption lines from the WD that are not shifted: Si iv (1066), O iv (1068) and S iv (1073). The O iv line do appear in very hot WDs and is a sign that the WD in RU Peg is indeed relatively hot and is usually not observed in accreting WDs in CVs. The FUSE spectrum of the DN RU Peg in quiescence is modeled with a WD spectrum. The very high temperature of the model is needed to fit the flux level of a massive (and therefore compact) WD (i.e. to fit the distance) and to account and fit properly the S iv (1073), Si iv (1066), and O iv (1068) absorption lines. The FUSE spectrum of this system was processed and modeled in Godon et al. (2008).

          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., Barrett, P.E., Hubeny, I., Linnell, A.P., Szkody, P. 2008, ApJ, 679, 1447

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.