low res observations of SS Cyg

Home Forums Spectroscopy low res observations of SS Cyg

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  • #574418
    Kevin Gurney
    Participant

    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

    Attachments:
    #581451
    Paul Leyland
    Participant

    Nice!

    #581453
    Peter Mulligan
    Participant

    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  

    #581454
    David Boyd
    Participant

    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

    #581455
    Kevin Gurney
    Participant

    Hi David

    Thanks for astrophysics notes…

    E&T website?

    Kevin

    #581456
    Andrew Smith
    Participant

    Equipment  and Techniques look right hand side to “Sections” links

    Regards  Andrew 

    #581457
    Kevin Gurney
    Participant

    Hi Andrew

    Thanks -got it,

    …am grappling with the method David gives now 🙂

    Cheers

    Kevin

    #581458
    Robin Leadbeater
    Participant

    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

    #581459
    Kevin Gurney
    Participant

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

    See attached for results.

    Kevin

    #581461
    Kevin Gurney
    Participant

    Hi Robin

    Thanks for sharing…

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

    Cheers

    Kevin

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