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low res observations of SS Cyg

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k.gurney's picture
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low res observations of SS Cyg

An oft-visited target I am sure, but this was my first first look at this star over several nights (mainly in August). I am still amazed how stellar dynamics can be seen  from your backyard... details in the attached file.

Kevin

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Xilman's picture
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SS Cyg specroscopy

Nice!

pmulli's picture
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SS Cyg

Hi Kevin

The spectra are dynamic like you say, are the strong emission lines early on due to mass transfer from the red dwarf onto an  accretion disk around the white dwarf, causing disk instability and increase in light.  Or does matter impinge onto the surface of the white dwarf increasing  the systems light output, or is it a bit of both.  Probably am i right in saying its a little more complicated than that.  Anyway nice piece of work

Peter  

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SS Cyg

Hi Kevin,

In quiescence, during your first 3 spectra, SS Cyg has a relatively stable accretion disc which is being fed from the secondary star and is in turn transferring this hydrogen-rich material onto the surface of the white dwarf. This process produces the Balmer emission lines you see in the quiescent spectrum. When the star goes into outburst, the temperature of the disc increases elevating the blue end of the continuum, singly ionised helium HeII lines appear, and the opacity of the disc increases which absorbs some of the emerging light generating the absorption component of the spectral lines and reducing their emission component. This is a rather simplified description but conveys the general picture.

If you want to see how you can accurately flux calibrate your spectra using a V magnitude, have a look at my workshop slides in the spectroscopy section of the E&T website.

David

k.gurney's picture
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SS Cyg

Hi David

Thanks for astrophysics notes...

E&T website?

Kevin

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Equipment  and Techniques

Equipment  and Techniques look right hand side to "Sections" links

Regards  Andrew 

k.gurney's picture
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Hi Andrew

Hi Andrew

Thanks -got it,

...am grappling with the method David gives now :)

Cheers

Kevin

Robin Leadbeater's picture
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Also with Star Analyser

Hi Kevin,

There are a couple of people on the AAVSO forum looking at SS Cyg using Star Analysers with some success. I have been pointing them to yours (and others), spectra in the BAA database :-)

Cheers

Robin

k.gurney's picture
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also with SA

Hi Robin

Thanks for sharing...

It looks a really good object for the ALPY (and apparently SA too..)

Cheers

Kevin

k.gurney's picture
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flux calibration

I have used the Method outlined by David in his slides and spectro-aras posting...

See attached for results.

[I think what I did before was equivalenet to treating the first spectrum as magnitude zero - everything scaled wrt that]

Kevin

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