Observation state of the campaign

VV Cep 2017-2019 Campaign
Moderator for this forum: Ernst Pollmann

Re: Observation state of the campaign

Postby Andrew Smith » Sun Aug 05, 2018 1:17 pm

Thanks for you patients Ernst. Looking at your model on page 5 of this thread it would be good if you and your team could try to predict what will happen as the B star emerges from the eclipse. Then the model can be tested against the observations rather than retrofitted.

Maybe other options (if there are any realistic ones) could also be modeled and see which fit best.

Regards Andrew
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Re: Observation state of the campaign

Postby Peter Somogyi » Sun Aug 05, 2018 2:05 pm

Ernst,

To answer:
"What, if the inclination angel of the rotational axis of the B star (and hence the rotational axis of the emission region) related to the orbit has changed? "

To determine if it was maybe an inclination change, my suggestion was to get the barycenter of H-alpha profile high velocities region (170-400 km/s) in longterm, and follow its velocity change:
Halpha_eclipsed_vs_noneclipsed_RVs.jpg
Halpha_eclipsed_vs_noneclipsed_RVs.jpg (37.23 KiB) Viewed 3670 times

This figure has a Mu Cep subtracted (tellurics removed), to present the pyramid's outer (= in fact the B nearby area) region that has really been eclipsed.
That data is extractable I think, could use the M profile for a precise RV fitting. Of course, it would be a huge work, and needs many years of data.
The R/V EW ratio graph - not splitted to the higher 170-400 km/s velocities that claimed to be close to B - is not speaking to me in regards with orbital information.

Peter
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Re: Observation state of the campaign

Postby Ernst Pollmann » Sun Aug 05, 2018 3:18 pm

Hi Andrew,
the question what happens if the B component becomes visible and what will be observable might be (theoretically) "easy" [(:-)] to describe: the inverse process of the beginning of the eclipse. Sorry, this was a joke only.
But in order to answer in a pragmatically way I would say: let´s wait and see.
Do you agree ?

Ernst
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Re: Observation state of the campaign

Postby Ernst Pollmann » Sun Aug 05, 2018 3:46 pm

Peter,
your suggestion does have a large affinity with the philosophy of evaluation of Wright (1977). Actually he determined the velocity of the both Halpha components. But he did it while his observations was running, whereas "we" would have to evaluate a huge amount of spectra under your suggested point of view after the event.
If we could find someone, who were able to develope a special program tool for fits-spectra in order to do this evaluation job, that would be great.

Ernst
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Re: Observation state of the campaign

Postby Benjamin Mauclaire » Sun Aug 05, 2018 8:25 pm

Such massive processing is possible with SpcAudace.
It is designed for such tasks.

For example, I had to manage more than 250 spectra for eps Aur 2011 survey:
http://adsabs.harvard.edu/abs/2012JAVSO..40..718M
Fig. 3 shows EW variations within time. Measurements and uncertainties were done with only one available all in one function.

Actually working on RR Lyr campaign data, it is several thousands spectra that it is managed.
And if more complex tasks have to be computed, you can do scripting.
This has been usefull to compute phased figures 2 and 3 in our last paper:
http://adsabs.harvard.edu/abs/2017A%26A...607A..51G

Benji
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Re: Observation state of the campaign

Postby Ernst Pollmann » Sun Aug 19, 2018 1:14 pm

Information about the observation campaign of VV Cep:
1) Continuity of the 43 day precession period
2) uniform decrease of the amplitude.
vvcep.png
vvcep.png (178.19 KiB) Viewed 3561 times

Thanks a lot to all participants of the campaign who enables this continuing study!

Ernst Pollmann
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Re: Observation state of the campaign

Postby Ernst Pollmann » Sun Sep 16, 2018 7:59 am

Dear colleagues,

the investigation presented here is the measurement of the radial velocity (RV) of the violet component of the Halpha emission.

For this purpose only spectra are used, which have been taken with LHIRES III spectrographs by five different ARAS observer. With these spectrographs the spectral resolution is high enough to measure the RV precisely.

The spectra are re-calibrated with lines of the M star (FeI = 6546.245; TiI = 6556.066; CaI = 6572.781; FeI = 6593.878). These RV measurements relative to the RV of the M star have been done with VSpec, by wavelength determination of the peak maximum of the violet component of the Halpha emission. The error of wavelength calibration in that way is approx. (+/-) 1km/s, mostly less.
radial velocity.png
radial velocity.png (158.11 KiB) Viewed 3413 times

A comparison of the RV with the V/R curve shows the obvious antisynchronous behavior of both. Unfortunately the density of the 135 spectra for the determination of the radial velocity observation is clearly lower than for V/R, so it is hardly possible to find there the 43 day period.

But the fact of the antisynchronous behavior of the RV of the blue component to V/R, boost the thesis that the observed 43 day V/R period is caused by a precession movement (RV) of the disk- or shell-like emission source around the B star.

Ernst Pollmann
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Re: Observation state of the campaign

Postby Ernst Pollmann » Thu Sep 20, 2018 3:53 pm

Dear colleagues,
the report above have been extended with radial velocity measurements of the V-component of the Halpha double peak emission in order to find an explanation for the 43.5 day Period of V/R.
See:
http://astrospectroscopy.de/media/files ... _vvcep.pdf

Ernst Pollmann
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Re: Observation state of the campaign

Postby Ernst Pollmann » Thu Dec 20, 2018 4:23 pm

Dear colleagues,
the evaluation of the ARAS Halpha EW monitoring has led to the following times of the eclipsing phases:

As Fig. 1 shows, it is hardly possible to define a reliable time for the beginning of the eclipse (phase T1). The reason is the overlayed periodic variation with a period of 43.5 days. The B mag light curve of the BAV defines JD 2457953 (predicted JD 2457970). See:
https://www.bav-astro.eu/index.php/vera ... p-kampagne
Fig. 1.png

Fig. 2 enables the determination of Phase T2 & T3:
Phase T2: can be devined at JD 2458085 (predicted JD 2458054).
Phase T3: can be devined at JD2458419 (predicted JD 2458521).
Totality phase = 334d (predicted 467d)
Fig. 2.png
Fig. 2.png (86.24 KiB) Viewed 2851 times

This preliminary data suggest the assumption that the size of the disk-like emission source around the B star has reduced since the last eclipse in 1998. A "small" (or smaller) disk is in harmony with the 43.5 d period of the V emission (already published here). Also the smaller depth of the EW level during the totality (only -4.2 A in average) fits to this fact.

Ernst Pollmann
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Re: Observation state of the campaign

Postby Ernst Pollmann » Tue Dec 25, 2018 2:11 pm

Dear colleagues,
the Halpha V/R time behavior became to a main observation part of our campaign. This time behavior with its surprising periodic character is shown in Fig. 1 (blue curve) and leads to the question of the causes of that phenomenon.

The V emission arises in the shock front area in front of the B star which moves with supersonic velocity through the stellar wind of the M star. The R emission arises in the outflowing zone behind the B star.

The meanwhile comprehensive data base enables to analyze the separate, quantitative contributions of the V and the R emission component to the ratio V/R. This is shown in Fig. 2. We can see that V correlates with the ratio V/R to 84%, R correlates only with 34%.

Therefore we can say that essentially the V emission is responsible for the V/R periodicity in Fig.1.

This periodicity leads to the question of the influence of the radial velocity (RV) of the V emission component. In Figure 3 is drawn the RV of the V peak against its emission maximum, and it shows, RV is correlated with the V line flux maximum to approx. 70%.

This result suggests that the V-emission area in front of the B star periodically moves back and forth in the observers line of sight, and there is reason to believe that there is a librational motion of the disc structure around the B star.
periodic RV of the V emission.png
periodic RV of the V emission.png (181.15 KiB) Viewed 2783 times

Comments are welcome!

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