VV Cep: Fe absorptions increase around Ca II doublet

VV Cep 2017-2019 Campaign
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Re: VV Cep: Fe absorptions increase around Ca II doublet

Postby Peter Somogyi » Sat Oct 07, 2017 2:20 pm

Based on Robin's observation + and BAV homepage 1.5-1.7 Umag drop has just happened as in the past, light from the B component must be mostly out for now (yet to wait for making sure there is no more drop).

However, let me remind everyone, then we are now in a critical phase for the higher Balmer lines - as I've taken my lower UV region, Balmer is still there, suspectedly some parts still coming from the remaining internal part of an internal disk:
vvcep_20170908_vs_1001_PSO.png
vvcep_20170908_vs_1001_PSO.png (80.73 KiB) Viewed 1390 times

asdb_vvcep_20171001_738_lineid.png

(Could not subtract M component yet for this region, need to wait till Alp Ori is up. Have Mu. Cep that is too far from perfect to subtract at this higher ratio.)
If our speculation is right and an internal disk exists with the high Balmer lines, we should see now how the above H14-H9 lines get "switched off" week by week!
As I've looked through the literature, no other known emission exist this region than 3806 [Cu II] (+ Balmer), so I expect the outstanding emission at H11 is really from H11.
Unfortunately, weather is poor here, but now I'd chose this region to follow next.

Cheers,
Peter
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Re: VV Cep: Fe absorptions increase around Ca II doublet

Postby Peter Somogyi » Sat Oct 21, 2017 10:43 am

Status of Balmer changes in the UV end:

vvcep_uv2_20171001_1019.gif


It is surprising to see V/R variations and both wings up - it contradicts with the theory that it's from a B component's disk, whilst the B core by now is obviously in eclipse.
I did take a CaII region again on 2017.10.15, and it perfectly matches with the state of 2017.09.22 (= my 1st detection of eclipse event).
Sent all to the database.

Peter
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Re: VV Cep: Fe absorptions increase around Ca II doublet

Postby Ernst Pollmann » Sat Oct 21, 2017 4:10 pm

Hi Peter,
you wrote:
… it contradicts with the theory that it's from a B component's disk…

M. Saito et al. wrote in Publ. Astron. Soc. Japan 32, (1980):
Image1.png
Image1.png (18.9 KiB) Viewed 1363 times

If we take into account that kind of possible variabilities of the M star, then the variations in your spectra does not contradict at all the "theory of the disk variability". Also the frequency of your measurements is to low to claim that.

Best wishes,
Ernst
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Re: VV Cep: Fe absorptions increase around Ca II doublet

Postby Robin Leadbeater » Sat Oct 21, 2017 11:29 pm

Hi Ernst,

The reverse is also true. As Dr Bob Stencel explained during the eps Aur campaign when I was trying to understand what was happening to H alpha in that system. "The problem with Hydrogen is it is everywhere". There are many potential sources of H emission in these types of systems (stellar wind, chromosphere, mass transfer streams, disks, accretion hot spots...) These will also impact the measurement of variability at H alpha. The simple assumption that H alpha emission variability uniquely describes just a circumstellar disk will be inadequate. Our expertise in observing, not theorising. I find that is best left to professionals.

Cheers
Robin
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Re: VV Cep: Fe absorptions increase around Ca II doublet

Postby Peter Somogyi » Sun Oct 22, 2017 8:44 am

Hi Ernst,

Thank you for looking at it! Actually I don't contradict to your theory here:
"...then the variations in your spectra does not contradict at all the "theory of the disk variability""

To be more precise, my statement is: my spectra show contradiction with a possibility, that the most of H11 would come from a B disk's emission. (Same applies to H10.)

Because if it would, we wouldn't see both R and V wings still prominent, once after B went into eclipse:
vvcep_H11_cmp_pre_post.jpg

It is enough to know that the continuum part from B component dropped by 1.5 mag by now (see the already available Umag series) whilst M / B component ratio in this region was like 1/6 before the 1st contact, nowadays it should be like 1:1 very roughly (lower region, that's why not 1:2 that I measured for CaII). Some little continuum variation doesn't matter.
If H11 was mostly coming from a B star's disk, then both of its R and V wings should have been decreased a lot (as M continuum is coming up by a 2.5x factor), together with the B continuum.
The contrary has happened, V wing doubled and R wing remained prominent (see my graph above), well explainable by an external source (external from B), with a time coincidence by the eclipse event.
And, my +1 extra statement that it does have its own R/V variation - time is resolution is irrelevant here, I am not stating exactly what kind of variation it is or what's the period (still would be interesting to correlate the EWs with H-alpha). It is just rotating, that's clear to see.

Of course, some of the H-alpha variability (little or large portion: ?) may still be coming from a B star's disk. But, mostly not the H10-11.

Cheers,
Peter
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Re: VV Cep: Fe absorptions increase around Ca II doublet

Postby Ernst Pollmann » Sun Oct 22, 2017 12:04 pm

Hi Peter,
despite all the detailed considerations the main question remains: how deep we are in the eclipse?
If we have a look at the Umag measurements of P. Sterzinger (BAV) one have the impression that the B star meanwhile is eclipsed totaly. This would mean on the other hand that also the "first half" of its disk (the blue shifted part) should be eclipsed meanwhile.
This assumption is in agreement with the Halpha EW monitoring (attached plot). It shows at present a approx. 50% reduction of the initial value at JD 2457700.
These both fact says that we are observing right now (more or less) the "second half" of the disk, that is to say, we see the inner part (H10, H11) of that portion until the outer part (Halpha) of the disk. This means further that the total eclipse is right in front of us.
My personally expectation is that the amplitude of the V/R oscillations (not rotation as you says) of H10, H11 & Halpha becomes smaller and smaller the more the disk is eclipsed.
vvcep_halpha-monitoring.png

Ernst
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Re: VV Cep: Fe absorptions increase around Ca II doublet

Postby Peter Somogyi » Sun Oct 22, 2017 3:24 pm

Hi Ernst,

It is good that I published my observation with a suggestion what it tells, because I will not repeat it, and your H-alpha serie won't make me withdraw it either.
In general, your H-alpha serie (especially the previous eclipses too rare data) is not enough accurate and/or conclusive for the Umag contact state, and vice versa. Some 1-month accuracy correlation is detectable by a hard human look, and it is also well expected to have the H-alpha contact times blurred by month(s).

As for the Umag contact times length: I can find a big discrepancy between the observations of 1976-78 (your mentioned 1980 M.Saio, H.Saito) and 1997/98 (1999, Leedjarv, "The 1997/1998 eclipse of VV Cephei was late").
The data from 1976 show a much longer delta between 1nd and 2nd contact (hard to take out on Fig. 1: 250 days? - seems more to be an elongated "U" shape), but the the doc from 1999 tells explicitly 1st and 2nd (U-B) contacts a difference of 75 days (see Table 1.: 50620-50545) with a straight cutoff as a lows state. That 75 days is not far from my actual state assessment, though I admit we seem to be a little bit shorter (like a 20%).

Let's observe more, and time will tell.

Cheers,
Peter

PS.: there's a 2nd document about 1997/98 event: "1999 Mikolaewski, THE SUDDEN PERIOD CHANGE OF VV CEPHEI", but its UBV graph looks to be a duplicate, telling about a similar drop by 1.6 Umag within a 70 days.
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Re: VV Cep: Fe absorptions increase around Ca II doublet

Postby Robin Leadbeater » Tue Nov 21, 2017 11:20 am

Robin Leadbeater wrote:As Dr Bob Stencel explained during the eps Aur campaign when I was trying to understand what was happening to H alpha in that system. "The problem with Hydrogen is it is everywhere". There are many potential sources of H emission in these types of systems (stellar wind, chromosphere, mass transfer streams, disks, accretion hot spots...) These will also impact the measurement of variability at H alpha. The simple assumption that H alpha emission variability uniquely describes just a circumstellar disk will be inadequate.


See comment posted today by Phil Bennett here for example
viewtopic.php?f=19&t=1797&start=20#p9759

Robin
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Re: VV Cep: Fe absorptions increase around Ca II doublet

Postby Peter Somogyi » Tue Nov 21, 2017 8:30 pm

I think we can start collecting the T2 times of different Balmer lines - except H-alpha that possibly yet needs to be waited to finish its variations (if it will).

Balmer lines we observed as disappeared so far:
H8: disappeared between Oct.24 - Nov.06 (should be closer to 10.24), see: viewtopic.php?f=19&t=1822&start=30#p9668
H-beta around Nov.18 (thanks for Hugh), as per viewtopic.php?f=19&t=1797&start=20#p9747

And, here is the H12-H9 region, having Alp Ori 1:1 subtracted (normalised for 3780-3785) and +0.5 value added for PlotSpectra, showing my serie and last 2 ones from James Foster + my last on Nov.03:
vvcep_cmp_all.png

We are setting scope and spectroscope focus on H11-H9, edges have either lack of signal and/or wavelength calibration may get inaccurate.
And, I think H11/H10 was settled already on Nov.03 (+2 spectra by James confirming).
James doing different flat handling (internal lamp whilst I use an UV lamp) hence I suspect a hole difference at 3790A, and I was dividing his spectra by a low order spline fitting to my curvature on 11.03.

One thing to note, H11 (and maybe H10) show constant emission, falling out of the rule of thumb that only H-alpha would remain.

- Peter
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Re: VV Cep: Fe absorptions increase around Ca II doublet

Postby Ernst Pollmann » Wed Nov 22, 2017 9:35 am

Peter,
thanks for this well understandable compilation of the disapearance of the higher Balmer lines. Obviously is the subtraction of the alpha Ori spectrum a successful way to demonstrate that. We have to wait and see, how H10 and H11 will behave during the next days.
In any case we should to aspire a summary for the time period T1 to T2 of our both monitoring parts with Phil Bennet in order to clarify and or emphasize the main results we have gotten so far. I think it make sence to publish both aspects of our observations in a common summary. Hope you agree.
I will write him a message in that sence.

Best wishes,
Ernst
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