H alpha Periodicities in the Spectrum of Alpha Cygni

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H alpha Periodicities in the Spectrum of Alpha
Cygni
Noel Richardson The University of Toledo Advisor
Dr. Morrison
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Some Interesting Facts about Alpha Cygni
Type A2Iae
Luminosity is 160000 times that of the Sun
Diameter 180 solar (measured)
200 solar (calculated)
Approximately 2600 light years away
If placed at the distance of Vega, it would be as
bright as a well developed crescent moon.
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How to find Alpha Cygni
Right Ascension 20h 41m 29s Declination 45 17'
09" epoch 2001.5
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The Spectrum of Alpha Cygni
Shows a weak P Cygni profile, which signifies
mass loss
Estimated mass loss is 0.8 millionths of a solar
mass each year
Spectrum is slightly variable
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Our project
Look at spectra taken at Ritter Observatory
Create a dynamical spectrum to look for
periodicities in the H alpha region of the
spectrum.
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Spectrum taken on March 26, 2001
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Telluric Lines
Absorption features produced by the Earth's
Atmosphere
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Removal of Telluric Lines
Use a hot rapidly rotating star, such as sigma
Sagittarii or zeta Aquilae
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IRAF allowed us to fit Gaussian curves to the
telluric lines.
Normalized Flux
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Then, IRAF constructed an artificial
spectrum that was a telluric standard.
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With the IRAF task telluric, the spectra are
divided by a telluric template, removing the
unwanted absorption features.
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Finally, the continuum of the spectra is
normalized so that all the spectra are easy to
compare.
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A look at an absorption event
Several Events took place in the 2001 observing
season
June 9
These were not the only spectrum changes, but the
ones with the most data points.
September 6
November 1
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These spectra will be combined into a dynamical
spectrum. This is a dynamical spectrum for the
1997 observing season.
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Conclusions
Events occur approximately every 40 days
Not all events are the same.
Spiral shaped density enhancements in the stellar
wind
More data needed
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Acknowledgments
Dr. Nancy Morrison
Chris Mulliss
David Knauth and John Wisniewski
Ritter Observing Team