In the spectral eclipse mapping we have used the spectral lines as single wavelength bins.
Full lines show the best sinusoidal fit to the data.
III emission on top of a flat or slightly blue continuum. These three unusual features show that the emission lines are formed in a site with a higher than usual ionization level. Furthermore, the system is approximately 1.2 mag fainter than when observed by Penning et al. 6.2 Multiple emission components We have binned the data in 50 phase bins and subtracted the underlying continuum by making a linear fit to adjacent wavelengths. The trailed spectra of the main emission lines are shown in Fig. 8 .