Subfeatures < 0.5% of continuum were detected moving through the line profiles of the Be/shell star y Cas over a nine-month period in 1983. While the average spacing and acceleration of the subfeatures is consistent with nonradial pulsation of |m| = 12 +/- 4, large variations in the acceleration of the subfeatures are sometimes seen and some subfeatures appear and disappear suddenly. The subfeatures appeared particularly chaotic on 1983 October 26, five days prior to detection of a strong X-ray flare with the Tenma satellite. The observed period of the subfeature oscillations varies between 7000 and 10,000 seconds which is similar to the transient 6000-second variation in X-ray flux found by EXOSAT in December 1984. No rapid E/C variation is observed in the Hy and He I _5876 emission-line profiles (Refer to PDF file for exact formulas).

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This article may also be accessed on the publisher's website at: http://articles.adsabs.harvard.edu/cgi-bin/nph-iarticle_query?1988PASP..100..233Y&data_type=PDF_HIGH&type=PRINTER&filetype=.pdf We thank Drs. G.G. Fahlman and M.A. Smith for helpful comments and suggestions. This research was supported by funds granted to one of us (G.A.H.W.) from the Natural Sciences and Engineering Research Council of Canada.ISSN:1538-3873 Note: imported from RIT’s Digital Media Library running on DSpace to RIT Scholar Works in February 2014.

Document Type


Department, Program, or Center

Chester F. Carlson Center for Imaging Science (COS)


RIT – Main Campus