AAS 206th Meeting, 29 May - 2 June 2005
Session 35 Stars
Poster, Wednesday, 10:00am-7:00pm, Thursday, 9:20am-2:00pm, June 1, 2005, Ballroom A

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[35.07] Deneb: Five Years of H Alpha Monitoring

N. D. Morrison, N. D. Richardson (U. Toledo), E. Allgaier (American U.)

Ritter Observatory's archive of spectra of Deneb covers the period 1993 through the present. In an initial survey of the archival data, we studied the H alpha region of 339 spectra taken during the 1997-2001 observing seasons with the 1-meter telescope and its fiber-fed spectrograph, which has a spectral resolving power of 26,000. The present results are based on inspection of dynamical spectra constructed with IRAF and SAOImage DS9. Telluric absorption lines have been removed. The H alpha profile has a P Cygni morphology, with an emission component that is highly variable in strength. Superimposed on blue wing of the absorption component, there is almost always a secondary absorption feature at a radial velocity of about -100 km s-1. Sometimes the feature progresses to more negative velocities, as do DACs in P Cygni wind lines in hotter stars, but sometimes the feature remains stationary. In 1997, it exhibited cyclical behavior, with ``absorption events'' occurring approximately every 40 days. There is subtle evidence of similar behavior in 2000, but in the other years, the waxing and waning of the feature appear to be largely stochastic.

Research at Ritter Observatory is supported by The University of Toledo, the Fund for Astrophysical Research, and the American Astronomical Society Small Grants Program (NASA funds). Community access to the facility is supported by NSF-PREST. Allgaier's participation was supported by the NSF-REU program.

The author(s) of this abstract have provided an email address for comments about the abstract: nmorris2@uoft02.utoledo.edu

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Bulletin of the American Astronomical Society, 37 #2
© 2005. The American Astronomical Soceity.