Observation report 2012/13 of the Hα- and He6678 monitoring of ζ Tau
Fig. 1 (above & middle): Hα-Profile
the central absorption core of the Hα-profile reached its max. depth on 10. Feb. 2013 (JD 2456334). It indicates the min. size (volume) of the gas disk around the primary. It´s the first time, that an EW (disk) minimum for ζ Tau have been observed at a certain date.
Fig. 1 (below): Hα-EW
EW reached its historical min. at the same time. Newest measurements do show a slow rise now.
Fig. 2: Hα-V/R
Corresponding the disk size minimum and the low EW level of Hα, very small V/R activities. We can expect a rise of it during the next visibility of the star.
Fig. 3: HeI6678
Fig. 3 shows the phase behavior of the well-known 132.9735d-period [1, 2, 3]. Observer of the campaign 2012/13: C. Sawicki, St. Charbonnel, B. Mauclaire, E. Pollmann.
The relatively large RV scatter could be caused by ultra-short-term variations, due to co-rotating clouds and/or non-radial pulsations of the primary.
 Ruzdjak, D., et al., A&A, 506, 1319-1333, 2009
 Harmanec, P. ,1984, Bull. Astron. Inst. Czech., 35, 164
 Pollmann, E., Mauclaire, B., Bücke, R., IBVS 6099
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