Time resolved optical spectroscopy of the eclipsing intermediate polar EX Hydrae.
Abstract
Time resolved spectroscopy of the eclipsing intermediate polar EX Hya has been obtained. The authors confirm that the dominant variation in the spectral line flux occurs with the 67-min white dwarf rotation period and is in phase with the 67-min optical and X-ray continuum variation. Further, they find that the pulse fraction is greatest in the wings of the emission lines and that there is a variation in the relative strengths of the blue and red line wings on the 67-min period. No evidence is found for an occultation of the line flux corresponding to the narrow continuum eclipse that recurs every 98-min orbital cycle. The authors do, however, find changes in the line profiles that extend for ≡0.15 of the orbital cycle, either side of the photometric eclipse. These they interpret as a progressive occultation of a rotating accretion disc by the companion star. The emission line data are interpreted in terms of three components: double peaked emission from a disc, an S-wave component caused by a bright region on the outside of the disc, and emission pulsed with the 67-min period which originates close to the white dwarf.
- Publication:
-
Monthly Notices of the Royal Astronomical Society
- Pub Date:
- September 1987
- DOI:
- 10.1093/mnras/228.2.463
- Bibcode:
- 1987MNRAS.228..463H
- Keywords:
-
- Eclipsing Binary Stars;
- Temporal Resolution;
- Visible Spectrum;
- White Dwarf Stars;
- Emission Spectra;
- Line Spectra;
- Spectral Energy Distribution;
- X Ray Spectra;
- Astrophysics