28 Tau Halpha-V/R and Radialvelocity

[Ernst Pollmann]

Dear 28 Tau observers,
your commitment, to observe this star, did lead during the current visibility to a first success in monitoring of Halpha-V/R and radial velocity (see attachment).
Corresponding to my attached observation notes (for J. Nemravova, Hvar conference, July 2012), we could confirm the anti-correlated behavior of V/R and RV. This behavior of the star has been not observed of the professionals so far.
The radial velocity has been evaluated at the Halpha absorption core with the mirror technic of corresponding BeSS spectra. It seems, that our different spectra provides a fairly well consistency in this parameter. It would be great, if you could continue your important observations.
After ending of this observation campaign in early spring 2013, we could discuss our results with J. Nemravova, J. Katahira and Petr Harmanec, and publish afterwards.
One of the main question is: is the companion star responsible for the V/R changes or not. If not, what causes this? Do you have any recommendations or ideas?

Ernst Pollmann
Active Spectroscopy in Astronomy
http://www.astrospectroscopy.de
http://www.astronomie.de/astronomische- ... ktroskopie

[Ernst Pollmann]

Based on a common observation campaign at 28 Tau, we have been able to detect the last periastron.
Accordingly J. Nemravova´s ephemeries (in A&A, March 2010) and a 218d-period, we could expect a periastron at JD 2456172.
Our observation campaign did lead to an periastron at JD 2456189 (see attached Fig.)
Follow up observations during the current visibility period will hopefully show, whether the period did change or "something else".
Comments are welcome!

Ernst Pollmann
Active Spectroscopy in Astronomy
http://www.astrospectroscopy.de
http://www.astronomie.de/astronomische- ... ktroskopie