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AG Draconis annotated with line identification


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About this observation
John Coffin
Time of observation
14/09/2018 - 18:30
AG Draconis
Observing location
Essex, UK
Alpy 600
Atik 460 EX
Celestron 8 Edge HD with 0.7 x reducer
Lodestar off axis guiding
6 x 600s

This is an annotated spectrum of the symbiotic binary stars known as AG draconis. It has a period of about 550 days according to Wikipedia and has various outbursts. Symbiotic stars are important to astronomers because they are a "laboratory" for the study of accretion discs. The shape of the Raman OVI lines can help them develop models of the accretion disc around the white dwarf and the stellar wind from the secondary star. The ratio between the flux of the emission lines H beta and He II can be a proxy for the temperature of the white dwarf which in this particular spectrum would work out to roughly 100,000 degrees K. 

This spectrum is 2 - 3 A out on the wavelength calibration, an issue which I am trying to overcome. Eventually I hope to have spectra of good enough quality to upload to the BAA and ARAS databases and which will be of use to the professionals. 

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