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The ultraviolet variations of iota CasThe Ap variable star iota Cas was observed with the photometers on OAO-2 covering the spectral range 1430-4250 A. The ultraviolet light curves show a double wave with primary minimum and maximum at phase ? 0.00 and 0.35, respectively. Secondary minimum light is at phase ? 0.65 with secondary maximum at phase ? 0.85. The light curves longward of 3150 A vary in opposition to those shortward of this 'null region'. Ground-based coude spectra show that the Fe II and Cr II line strengths have a double-wave variation such that maximum strength occurs at minimum ultraviolet light. We suggest that the strong ultraviolet opacities due to photoionization and line blanketing by these metals may cause the observed photometric variations. We have also constructed an oblique-rotator model which shows iron and chromium lying in a great circle band rather than in circular spots.
Document ID
19770032365
Document Type
Conference Proceedings
Authors
Molnar, M. R. (Toledo Univ. OH, United States)
Mallama, A. D. (Toledo Univ. OH, United States)
Soskey, D. G. (Toledo, University Toledo, Ohio, United States)
Holm, A. V. (Wisconsin, University Madison, Wis., United States)
Date Acquired
August 9, 2013
Publication Date
January 1, 1976
Subject Category
ASTRONOMY
Meeting Information
Colloquium on Physics of Ap-stars(Vienna)
Distribution Limits
Public
Copyright
Other