Forum der Vereinigung der Sternfreunde

Dear all,

I am happy to see things moving on. I encourage everyone to share
their ideas and to discuss the project here, on this Forum.

I would like to discuss the pertinence of the choice of the targets. I
am myself very interested by the long term monitoring of WR 134,
because I believe that this project can really benefit from a Pro-Am
campaign. The following is a short paragraph that I would suggest to
the webmaster to put in a new section of the web page entitled
"Scientific Impact":
***

Morel et al. 1999, ApJ, 518, 428 ("A 2.3 Day Periodic Variability in
the Apparently Single Wolf-Rayet Star WR 134: Collapsed Companion or
Rotational Modulation?") have found a coherent 2.25+/-0.05 day
periodicity in the line-profile changes of He II 4686, although the
global pattern of variability is different from one epoch to another.
The same period has been (marginally) found in UBV photometry. This
makes it one of the three WR stars (with WR1 (Chené & St-Louis 2010,
ApJ, 716, 929) and WR6 (Morel et al. 1997, ApJ, 482, 470)) for which
large scale spectral variations, likely to be caused by the presence
of CIRs in the wind, have been observed. However, since then, WR 134
has never been monitored a second time. Hence, it would be valuable to
confirm the currently known period and variability pattern. Moreover,
none of these three WR star showing CIR has been monitored on a very
long time interval in spectroscopy. Such a monitoring would give us
information on the epoch dependency, the long term variability pattern
and the evolution of the period, if there is any. Also, it would be
very interesting to look for a periodicity in the epoch dependency; it
would give us invaluable information on the origin of CIRs (would it
by magnetic field activity at the surface, stellar pulsations or
something else)! Such study has never been done yet, since none of the
previous spectroscopic campaign has been covering more than a month
(contiguously).
***

On the other hand, I don't see yet how monitoring clumps in WR 135
could have an equivalent impact. Moreover, WR 134 would benefit from
the best time sampling possible, since the period is "only" 2.3 days,
and the complexity of the variations combined with the epoch
dependency renders difficult the analysis of datasets that are not
sufficiently intensives. Can someone tell me why we should "split" our
efforts on two stars and what would be the benefit of monitoring WR
135, considering that this star has been already extensively studied
by Robert 1992 (her PhD thesis) and Lépine & Moffat 1999 ApJ., 514, 909?

Long live the Pro-Am campaign 2013!

André-Nicolas Chené


------------------------------------------------------------------------

--------------------------
André-Nicolas Chené
Postdoctorado
Universidad de Concepcion
Universidad de Valparaiso




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----- Original Message -----
From: Andrenicolas Chene (fg-spek-convento@vds-astro.de)
To: fg-spek-convento@vds-astro.de (fg-spek-convento@vds-astro.de)
Sent: Thursday, December 08, 2011 10:07 AM
Subject: [fg-spek] Re: New ProAm campaign in 2013


Dear all,

Now, I would like to address the question of the spectral line(s) we want to monitor. In the project description, it is mentioned that HeII5411 is the ideal line for WR134. I agree that this line is nice, but I believe that HeII4686 is much better. It is bigger, hence easier to observe with the required S/N, and it is more variable, since its intensity depends of the density to the square. Therefore, I would put HeII4686 as the prime "target", and HeII5411 and HeI5876 as interesting lines to monitor, if available.

Cheer,

André-Nicolas Chené



--------------------------
André-Nicolas Chené
Postdoctorado
Universidad de Concepcion
Universidad de Valparaiso

Yes, but if one is restricted in wavelength coverage )non-echelle), then CIII 5696 is best for clumps in WR135.
Then HeII 5411 in WR134 is fairly close to that and better than HeII 4686. That's the main reason for choosing 5411 instead of 4686. But I agree that 4686 is to be preferred, if one has the choice (which one
may not with restricted coverage).

Hello Thomas and all other friends,

But the measurements on such faint stars ( 8.3 mag) are a big challenge for me and my optical set (C14, Lhires III slit littrow).

.

Lothar Schanne wrote: Hello Thomas and all other friends,


But the measurements on such faint stars ( 8.3 mag) are a big challenge for me and my optical set (C14, Lhires III slit littrow).


.


A big challenge for me also. I could perhaps get SNR >100 at 2.5A resolution with my 280mm aperture C11 and LHIRES with a 600l/mm grating.

I think there are not many amateur spectroscopists who have enough aperture (>=0.5m?) to meet the target of 1A resolution at 200 SNR in 1 hour on these targets.

Cheers
Robin

Secondly, what is the problem about continuum of WR star with eshell spectra ? Could you explain ?

Hallo,
Robin is right ..... the discussed stars are very weak .... at least fiber
coupled echellespektrographs can not be used here from amateurs..... Usual
slitspectrograh in the configuration as described by Lothar and Robin
seems possible for amateurs , especially if it can be tracked with high
precision even in the hour axis, so that the slit is illuminated without
interruption!!!

Where are the coordinates of the objects?

cheers berthold




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----- Original Message -----
From: Filipe Dias (fg-spek-convento@vds-astro.de)
To: fg-spek-convento@vds-astro.de (fg-spek-convento@vds-astro.de)
Sent: Sunday, December 11, 2011 4:05 PM
Subject: [fg-spek] Re: New ProAm campaign in 2013


Hi Berthold, I believe these are the details:

WR 134 / V1769 Cyg / HD 191765 / HIP 99377
RA: 20 10 14.20
Dec: +36 10 35.1
vmag: 8.23
type: WN6

WR 135 / V1042 Cyg / HD 192103 / HIP 99525
RA: 20 11 53.53
Dec: +36 11 50.6
vmag: 8.36
type: WC8

Cheers,

Fil.

On Sun, Dec 11, 2011 at 2:12 PM, Berthold Stober
)vds-astro.de> wrote:
: Hallo,
Robin is right ..... the discussed stars are very weak .... at least fiber
coupled echellespektrographs can not be used here from amateurs..... Usual
slitspectrograh in the configuration as described by Lothar and Robin
seems possible for amateurs , especially if it can be tracked with high
precision even in the hour axis, so that the slit is illuminated without
interruption!!!

Where are the coordinates of the objects?

cheers berthold







Fil.

Resolution should be no worse than 1 Å, i.e. normally 0.3-0.5 Å/pixel.

Signal-to-noise S/N should be no worse than 200.

A 1200 l/mm grating would be the best match to the required ~1A resolution but as far as I can tell, it is unlikely to be possible to reach the required SNR with this sort of aperture. I am waiting to see what Lothar with a LHIRES and Thierry with an eShel can achieve on these targets with their 350mm aperture C14s This should give us a good idea of what aperture will be needed.

----- Original Message -----
From: Lothar Schanne (fg-spek-convento@vds-astro.de)
To: fg-spek-convento@vds-astro.de (fg-spek-convento@vds-astro.de)
Sent: Monday, December 12, 2011 12:20 PM
Subject: [fg-spek] Re: New ProAm campaign in 2013


Robin Leadbeater hat Folgendes geschrieben: A 1200 l/mm grating would be the best match to the required ~1A resolution but as far as I can tell, it is unlikely to be possible to reach the required SNR with this sort of aperture. I am waiting to see what Lothar with a LHIRES and Thierry with an eShel can achieve on these targets with their 350mm aperture C14s This should give us a good idea of what aperture will be needed.
Hello Robin, Rainer ...

in the annex my simspec-excel-sheet with a combination of 3 gratings/slit withs.

To get a resolution of 1.3 Angstr. I have to take a (ruled and blazed) 1800 g/mm grating and a slit with of 50 um (in case of my C14 in the focus of telescope the figure size of a star is about 60 um (4" seeing) ). This combination seems me the best for my set... But test is better then calculation.
We will see.



Herzliche Grüße

Lothar

www.astrospectroscopy.eu
www.spectrosphere.de

Resolution should be no worse than 1 Å, i.e. normally 0.3-0.5 Å/pixel.

Hallo Rainer,

you are right, of course, there is a glitch in the website. I corrected it to "Resolution should be no worse than 1 Å, i.e. normally 0.3-0.5 Å/pixel dispersion. "

Resolution is always with respect to pure 2 pixel Nyquist criterion, although the true resolution requires a bit more like 3 pixel.

Cheers, Thomas

Resolution should be no worse than 1 Å, i.e. normally 0.3-0.5 Å/pixel dispersion.

Thank you Fil.....

berthold
: ----- Original Message -----
From: Filipe Dias (fg-spek-convento(==>)vds-astro.de ([email]fg-spek-convento(==%3E)vds-astro.de[/email]))
To: fg-spek-convento(==>)vds-astro.de ([email]fg-spek-convento(==%3E)vds-astro.de[/email]) (fg-spek-convento(==>)vds-astro.de ([email]fg-spek-convento(==%3E)vds-astro.de[/email]))

Sent: Sunday, December 11, 2011 4:05 PM
Subject: [fg-spek] Re: New ProAm campaign in 2013



Hi Berthold, I believe these are the details:

WR 134 / V1769 Cyg / HD 191765 / HIP 99377
RA: 20 10 14.20
Dec: +36 10 35.1
vmag: 8.23
type: WN6

WR 135 / V1042 Cyg / HD 192103 / HIP 99525
RA: 20 11 53.53
Dec: +36 11 50.6
vmag: 8.36
type: WC8

Cheers,

Fil.

On Sun, Dec 11, 2011 at 2:12 PM, Berthold Stober
)vds-astro.de> wrote:
: Hallo,
Robin is right ..... the discussed stars are very weak .... at least fiber
coupled echellespektrographs can not be used here from amateurs..... Usual
slitspectrograh in the configuration as described by Lothar and Robin
seems possible for amateurs , especially if it can be tracked with high
precision even in the hour axis, so that the slit is illuminated without
interruption!!!

Where are the coordinates of the objects?

cheers berthold








Fil.

Hi hANCk:

Yes, but if one is restricted in wavelength coverage )non-echelle), then CIII 5696 is best for clumps in WR135.
Then HeII 5411 in WR134 is fairly close to that and better than HeII 4686. That's the main reason for choosing 5411 instead of 4686. But I agree that 4686 is to be preferred, if one has the choice (which one
may not with restricted coverage).

Cheers, Tony

I personally believe that this idea gives a very interesting spin to our project! Going back to the very first WR stars discovered sounds exciting, don't you think? Moreover, there would be a real interest into monitoring WR 137 too.

----- Original Message -----
From: thierry Garrel (fg-spek-convento@vds-astro.de)
To: fg-spek-convento@vds-astro.de (fg-spek-convento@vds-astro.de)
Sent: Monday, December 12, 2011 7:18 PM
Subject: [fg-spek] Re: New ProAm campaign in 2013


Hi group !I started to observe WR134 tonigh under exellent condition and with my standart eshell companion.
Have a look here http://spectro-aras.com/forum/viewtopic.php?f=12&t=185
Cheers
T

2011/12/11 Berthold Stober )vds-astro.de (fg-spek-convento(==>)vds-astro.de ([email]fg-spek-convento(==>)vds-astro.de[/email]))>
: Thank you Fil.....

berthold
: ----- Original Message -----
From: Filipe Dias (fg-spek-convento(==>)vds-astro.de ([email]fg-spek-convento(==%3E)vds-astro.de[/email]))
To: fg-spek-convento(==>)vds-astro.de ([email]fg-spek-convento(==%3E)vds-astro.de[/email]) (fg-spek-convento(==>)vds-astro.de ([email]fg-spek-convento(==%3E)vds-astro.de[/email]))

Sent: Sunday, December 11, 2011 4:05 PM
Subject: [fg-spek] Re: New ProAm campaign in 2013



Hi Berthold, I believe these are the details:

WR 134 / V1769 Cyg / HD 191765 / HIP 99377
RA: 20 10 14.20
Dec: +36 10 35.1
vmag: 8.23
type: WN6

WR 135 / V1042 Cyg / HD 192103 / HIP 99525
RA: 20 11 53.53
Dec: +36 11 50.6
vmag: 8.36
type: WC8

Cheers,

Fil.

On Sun, Dec 11, 2011 at 2:12 PM, Berthold Stober
)vds-astro.de> wrote:
: Hallo,
Robin is right ..... the discussed stars are very weak .... at least fiber
coupled echellespektrographs can not be used here from amateurs..... Usual
slitspectrograh in the configuration as described by Lothar and Robin
seems possible for amateurs , especially if it can be tracked with high
precision even in the hour axis, so that the slit is illuminated without
interruption!!!

Where are the coordinates of the objects?

cheers berthold








Fil.














Thierry Garrel
Observatoire de Fontcaude, Montpellier, France
SpectroBlog http://gabalou.canalblog.com/

...and nobody speaks about this problem!!!

----- Original Message -----
From: Thomas Eversberg (fg-spek-convento@vds-astro.de)
To: fg-spek-convento@vds-astro.de (fg-spek-convento@vds-astro.de)
Sent: Tuesday, December 13, 2011 3:16 AM
Subject: [fg-spek] Re: New ProAm campaign in 2013


Hi Berthold!
Zitat: ...and nobody speaks about this problem!!!
But you do, and that is very good. We really need such kind of input so that possibly all problems will be solved this year. I mean, we have a good observers network and should frankly address these issues. Go ahead!

Thomas

Hi Teggoneggy!

That's a good argument (your arguments are far to often very good... ) and I can support it. Maybe my expectations are too high. It would be great to establish a REALLY large group being able to cover even WR 137. Perhaps we have the luck to welcome our highly active french friends to the team.

I suggest, we leave this open for a while and I add André-Nicolas' science case for WR 137 to the website with a specific remark that it is considered as a back-up target. What do you think?

Oh, I just see that Noel Richardson from Atlanda registered (Hi Noel). I invited him and Doug Gies to have a look on our discussion. Noel has already some nice ideas...

Cherio, Tomanaggo

PS: 1867 might be the birth of Canada but more important it is 2177 in the Babylonian Seleukidik era (whatever that is).

----- Original Message -----
From: Andrenicolas Chene (fg-spek-convento@vds-astro.de)
To: fg-spek-convento@vds-astro.de (fg-spek-convento@vds-astro.de)
Sent: Tuesday, December 13, 2011 7:52 PM
Subject: [fg-spek] Re: New ProAm campaign in 2013


I also agree with Tony... But I don't think we need to observe WR137 during the whole run. Neither WR135... Only WR134 would really benefit from a very long time span. So, why don't we do the following:

We observe WR134 as the prime target. Then, for a good fraction of the time, we also observe WR135, mostly trying to do a 24/24h coverage, which has never been achieved yet. Then, for a shorter amount of time (1-2 weeks), we can change WR135 for WR137. This would be somehow useful AND give us a nice story to tell Sky and Telescope.

Before organizing the schedule, we would first need to know how many observers+telescopes are involved, what are the capacities of all those spectrographs (resolution, Exp. Time required to reach S/N=100-200, wavelength coverage) before we decide who observes what star, what line and when.

AN

Thomas Eversberg wrote: Hi Teggoneggy!

That's a good argument (your arguments are far to often very good... ) and I can support it. Maybe my expectations are too high. It would be great to establish a REALLY large group being able to cover even WR 137. Perhaps we have the luck to welcome our highly active french friends to the team.

I suggest, we leave this open for a while and I add André-Nicolas' science case for WR 137 to the website with a specific remark that it is considered as a back-up target. What do you think?

Oh, I just see that Noel Richardson from Atlanda registered (Hi Noel). I invited him and Doug Gies to have a look on our discussion. Noel has already some nice ideas...

Cherio, Tomanaggo

PS: 1867 might be the birth of Canada but more important it is 2177 in the Babylonian Seleukidik era (whatever that is).



--------------------------
André-Nicolas Chené
Postdoctorado
Universidad de Concepcion
Universidad de Valparaiso

Hallo,

I would like to help in this campaign. But first I must convince myself (!) that I am able to make spectra of those stars with mag 8 producing a S/N of >/= 100.....I never before had tried it....and I am not shure if I can do it......

berthold

Please, put a significant SUBJECT to your posts.

Hi Berthold,

What S/N do you think you can reach in an hour? Depending on what you an do, we can see if we can "survive" with the combination of many 1h-observations.

AN

Berthold Stober wrote: Hallo,

I would like to help in this campaign. But first I must convince myself (!) that I am able to make spectra of those stars with mag 8 producing a S/N of >/= 100.....I never before had tried it....and I am not shure if I can do it......

berthold




--------------------------
André-Nicolas Chené
Postdoctorado
Universidad de Concepcion
Universidad de Valparaiso

there are some spectra from WR 140, this was the weekest star I explored systematically.

hi AN,

as said, I never tried to observe such stars of 8 mag or even weaker. You can find a lot of spectra I made in the past in the database in our forum, there are some spectra from WR 140, this was the weekest star I explored systematically......)

cheers berthold