VV Cep in eclipse

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  • #573853
    Robin Leadbeater
    Participant
    Attached are a series of spectra of VV Cep covering 3800-4150A at R ~2500 (variable 3000-1500 across the range  due to LHIRES chromatism)
     
    Note the loss of H Balmer emission, broadening of the Ca II H K lines and relative drop in continuum flux below ~4000A, particularly noticeable in the latest spectrum recorded 2017-09-26
     
    Robin

    #578581
    Jack Martin
    Participant

    Robin,

    Excellent work an interesting pattern.

    What is chromatism ?

    Regards,

    Jack

    Essex UK

    #578585
    Robin Leadbeater
    Participant

    I saw the same changes in the similar system AZ Cas in 2012 as it entered eclipse and we lost the spectrum of the hot B star  (Though there is no H Balmer emission in AZ Cas)

    http://www.threehillsobservatory.co.uk/astro/spectra_43.htm

    Cheers

    Robin

    #578584
    Robin Leadbeater
    Participant

    Hi  Jack

    Chromatic Aberration.  The inability of a lens to bring all wavelengths to focus in the same plane. The LHIRES uses an achromatic doublet which shows the usual pronounced chromatism in the Violet/UV so the focus varies across the spectrum. 

    Cheers

    Robin

    #578628
    Robin Leadbeater
    Participant

    Here is an updated plot including the latest spectrum from last night. There has been no further change in the past 9 days so it seems likely that the ingress phase is now complete at this wavelength.

    Robin

    #578630
    Ernst Pollmann
    Participant

    Dear colleagues,
    if you wants to be informed about the current Halpha observation state of the campaign, here the corresponding link:
    http://www.spectro-aras.com/forum/viewtopic.php?f=19&p=9412#p9412

    Ernst Pollmann

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