Orbit-Resolved H-alpha Emission in Three Selected Algols

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Session 85 -- Binaries
Display presentation, Wednesday, 11, 1995, 9:20am - 6:30pm

[85.13] Orbit-Resolved H-alpha Emission in Three Selected Algols

T. Hunt, R.K. Honeycutt (Indiana U.)

H$\alpha$ spectra of the eclipsing Algols SW Cyg, TZ Eri, and SS Cet were obtained using the 102-cm reflector at the U.S. Naval Observatory in Flagstaff. The observations cover the full orbits of each system, including eclipse phases. By subtracting the light of the stellar components, double-peaked emission lines are visible at nearly all phases for all three systems. At most phases, the blue-shifted emission is stronger than the red-shifted emission. There is also an absorption component present in each system that tends to be stronger after phase 0.5, where it also becomes more red-shifted.

In SW Cyg, the absorption is strongest just after phase 0.5, and has weakened by phase 0.8. Phases with the strongest absorption are the only phases where red-shifted emission is stronger than blue-shifted emission. In TZ Eri, strong absorption also appears just before eclipse, and here both emission lines are nearly equal in strength. In SS Cet, absorption begins increasing in strength after phase 0.5 until the beginning of eclipse, and there is no clear correlation between absorption and emission line strengths. The SS Cet system is very unusual in that there is a strong peak in the strength of both red-shifted and blue-shifted emission lines near first quadrature, and not at second quadrature, seen over multiple orbits.

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