H-alpha V/R time behavior in pi Aqr

Sunday 13 February 2011 by Ernst Pollmann

Halpha V/R time behaviour in pi Aqr

The V/R measurements in Hα spectra of the binary star π Aqr since October 2004 until today, makes possible an analysis of a possible periodic behavior. Fig. 1 shows the V/R time behaviour in seven visibility phases, fig. 2 shows in power spectrum a dominant frequency with a period of 83.3 d, and fig. 3 shows the phase diagram with the ephemerides:

JD 2453 345,7 + 83,9 * T

This period lies suspiciously near the orbital binary period of 84.1 d (see: The Astrophysical Journal, 573, 824, 2002 July10; K. Bjorkman et al.: „A study of πAqr during a quasi-normally star phase “).

Thomas Rivinius (ESO, Chile) confirms these data in his spectra, which were „almost without emission phase “. A cause for the finding of this periodicity is the „traveling emission component“, as it was found and examined in the mentioned paper during the B-phase of the star.

Since π Aqr in summertime is well observable, it would be desirably, if interested observers could dedicate themselves to this star. In addition, spectra, which not yet published in the data bases BeSS or (, would contribute for completion of the analysis. Fig. 1: Fig. 2: Fig. 3:

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