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Session 79 - CVs and Novae.
Display session, Wednesday, January 17
North Banquet Hall, Convention Center

[79.06] Hopkins Ultraviolet Telescope Observations of EX Hydrae

B. W. Greeley, W. P. Blair (JHU), K. S. Long (STScI)

We observed the intermediate polar EX Hya with the Hopkins Ultraviolet Telescope during the Astro-2 shuttle mission in 1995 March. The observation provides good signal to noise spectra on time scales of the order of 1 minute of the spectral region from the Lyman Limit to 1860 Å\ with a resolution of about 3 ÅThe total observation time was 32 minutes, and covers phase \phi_67 = 0.94 to 0.39 of the 67 minute white dwarf rotational period. At \phi_67 = 0.0, the spectrum shows strong emission by C \smallIV \lambda1549, C \smallIII \lambda977, \lambda1176, N \small V \lambda1240, Si \small IV \lambda1394, and a blend of lines including Ly \beta. The observed FWHM of the lines is about 2400 km s^-1, and decreases with phase. Weaker emission from C \smallII \lambda1335, He \smallII \lambda1640, and a blend of lines from 916-960 Å\ is also apparent. As the phase increases to 0.39, the average continuum level decreases by about 20%, while the line emission decreases by more than a factor of 4. The profile of the C \small IV \lambda1549 line changes considerably over the course of the observation, with a strong absorption appearing on the blue wing of the line from \phi_67 = 0.25 to the end of the observation. The ratios C \small IV/N \small V and C \small IV/C \small III do not show any significant trend with phase. We also see fluctuations in the continuum flux of \pm 30% on timescales of about 2 minutes during the second half of the observation.

This work was supported by NASA contract NAS 5-27000 to the Johns Hopkins University.

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