Observation by John Coffin: AG Draconis annotated with line identifi...

Uploaded by

John Coffin

Observer

John Coffin

Observed

2018 Sep 14 - 17:30

Uploaded

2018 Oct 31 - 12:20

Objects

Spectrum

Equipment

Alpy 600
Atik 460 EX
Celestron 8 Edge HD with 0.7 x reducer
AZ-EQ6
Lodestar off axis guiding

Exposure

6 x 600s

Location

Essex, UK

Target name

AG Draconis

Title

AG Draconis annotated with line identification

About this image

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.

Files associated with this observation

agdraconis_annotated.png (30.3 kB)

Like this image

Jeremy Shears, Andy Wilson

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