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Session 28 - Double Stars.
Display session, Tuesday, June 10
South Main Hall,
Both photometric and spectroscopic observations have been obtained of XX Cephei with the 40-inch Telescope at Mount Laguna Observatory. The photoelectric measurements were made in the Stromgren uvby system and na I filter during 1987 and 1988. The Wilson-Devinney program was used to model all five light curves simultaneously. The best photometric fit is for a semi-detached system with a mass ration of 0.2. The temperatures of the primary and secondary components are 7600 and 4250 K respectively. A new photometric period was determined, and the system appears to show abrupt period changes. Exploratory spectroscopic observations were made in the regions near 4500, 6500, and 8600 Angstoms searching for features from the cool secondary component. Re-analysis of older spectroscopic data from Struve suggest a Rossiter rotation effect in the velocity curve.
