Monitoring Radial velocity of the HeI6678 line of zeta Tau
Posted: Mon Oct 19, 2015 4:19 pm
Dear colleagues,
I would like to come back again to the campaign "Long-term Radial velocity Monitoring of the HeI6678 line in zeta Tau":
There were certain investigations of Stan Stefl and his colleagues (ESO) until (approx.) 2008, which have been continued by me and later in collaboration with colleagues of the ARAS group (see attachment).
Stan found a period of 1503 days, our monitoring however leads to a period of 1216 days. Enough reasons to continue, particularly since the reason for this kind of variability is still unknown until now.
The attached upper plot shows our RV monitoring with the long-term variability component (the short-term variability comes from the 132 day orbital period).The middle plot shows the long-term component with a fitted period of 1216 days (PDM analysis of the data in the upper plot).The lower plot shows the investigation of Stan until 2008.
I found a first BeSS spectrum of Tim Lester (2015-09-15) as a start of the campaign for the next months until (approx.) March 2016. It would be great, if other zeta Tau interested observers would contribute with their spectra.
Ernst Pollmann
----------------------------------------------
International Working Group ASPA
Active Spectroscopy in Astronomy
http://www.astrospectroscopy.de
http://www.astronomie.de/astronomische- ... troskopie/
I would like to come back again to the campaign "Long-term Radial velocity Monitoring of the HeI6678 line in zeta Tau":
There were certain investigations of Stan Stefl and his colleagues (ESO) until (approx.) 2008, which have been continued by me and later in collaboration with colleagues of the ARAS group (see attachment).
Stan found a period of 1503 days, our monitoring however leads to a period of 1216 days. Enough reasons to continue, particularly since the reason for this kind of variability is still unknown until now.
The attached upper plot shows our RV monitoring with the long-term variability component (the short-term variability comes from the 132 day orbital period).The middle plot shows the long-term component with a fitted period of 1216 days (PDM analysis of the data in the upper plot).The lower plot shows the investigation of Stan until 2008.
I found a first BeSS spectrum of Tim Lester (2015-09-15) as a start of the campaign for the next months until (approx.) March 2016. It would be great, if other zeta Tau interested observers would contribute with their spectra.
Ernst Pollmann
----------------------------------------------
International Working Group ASPA
Active Spectroscopy in Astronomy
http://www.astrospectroscopy.de
http://www.astronomie.de/astronomische- ... troskopie/