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 Post subject: Kap Dra
PostPosted: 14. May 2019, 00:34:34 AM 
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Neueinsteiger

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Hallo zusammen,

seit einigen Tagen habe ich den Lowspec (3D Druck, entworfen von Paul Gerlach) mit einem 1800er Gitter von Thorlabs in Betrieb. Nach den ersten sehr zufriedenstellen Tests habe ich nun begonnen, BE-Sterne und Doppelsterne in der Wellenlänge des Wasserstoffs zu beobachten.

Derzeit steht Kappa Draconis für mich recht günstig (habe leider eingeschränkte Sicht durch Bebauung). Anbei zwei Spektren vom 30.04.19 und 13.05.19. Ich möchte mich noch als Beginner bezeichnen und kann daher noch nicht alle physikalischen Zusammenhänge deuten. Hier interpretiere das nun so, dass die Dichte in der Gasscheibe nicht homogen verteilt ist und daher die Peaks im Spektrum unterschiedlich ausfallen. Kann ich hier direkt die Rotation der Gassacheibe beobachten ?

Sorry, die Bearbeitung ist noch verbesserungswürdig. Ich gewinne die Daten mit einem kleinen 80 mm APO. Das Gerät ist nicht unbedingt eine Lichtkanone. Viele meiner Aufnahmen sind daher noch etwas verrauscht. Vielleicht sollte ich länger belichten.

Viele Grüße

Hermann (der Spektro-Anfänger)


Ergänzung: Habe eben noch mit BASS die Wellenlängenverschiebung in Geschwindigkeit umgerechnet. Demnach würde auf meinen Aufnahmen der stärkere Peak - egal ob nun blau- oder rotverschoben - einen Wert von ca. 100km/s und der schwächere Peak etwa 70 km/s ergeben. Das würde sich mit meiner Vermutung decken. Die helleren Anteile im Spektrum befinden sich in Äquatornähe und rotieren entsprechend schnell. Nach außen hin nimmt Geschwindigkeit und Dichte/Helligkeit ab.


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File comment: Kap Dra am 30.04.2019 - aufgenommen mit dem Lowspec
Kap Dra am 30042019.jpg
Kap Dra am 30042019.jpg [ 313.22 KiB | Viewed 2054 times ]
File comment: Kap Dra am 30.04.2019
Kap Dra am 13052019.jpg
Kap Dra am 13052019.jpg [ 313.09 KiB | Viewed 2054 times ]
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 Post subject: Re: Kap Dra
PostPosted: 14. May 2019, 08:47:13 AM 
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Hallo Hermann,
ich freue mich hier endlich wieder einen Beitrag über Beobachtungen zu sehen. Ich habe mich bisher nicht mit kap Dra beschäftigt. Offensichtlich handelt es sich um einen Doppelstern. Näheres findest Du hier:
https://arxiv.org/pdf/1704.06751.pdf
Viele Grüße
Christian


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 Post subject: Re: Kap Dra
PostPosted: 14. May 2019, 12:49:22 PM 
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Hallo Hermann,

Gratulation zu dem ersten Ergebnis! Das sieht prima aus und macht Lust auf mehr. Länger belichten ist eine gute Option. Diese Spektren ändern sich nicht innerhalb kurzer Zeit. Die Scheiben vieler Be-Sterne sind inhomogen und zeigen diesen sich mit der Zeit ändernden Doppelpeak. Man nennt das V-zu-R-Variationen (V für Violett/Blau, R = Rot). Man nimmt an, dass sie durch eine lokale Dichteschwankung in der Scheibe erzeugt werden. Ja, Du siehst hier die Rotation der Gasscheibe. Die Natur von Be-Sternen ist jedoch noch immer nicht gänzlich geklärt. Sie sind wegen der starken Halpha-Linie schöne Beobachtungsobjekte, ein selbstkonsistentes Modell für eine kühle, ausgedehnte und stabile Keplerscheibe (Wasserstoff und Eisen) innerhalb eines heißen, radialsymmetrischen Sternwindes gibt es aber bis heute nicht. Sehr schwer zu verstehen. Das von Christian verlinkte Paper beschreibt eine durch einen Begleiter gestörte Scheibenstruktur. Das hat mit der eigentlichen Be-Frage weniger zu tun.

Quote:
Die helleren Anteile im Spektrum befinden sich in Äquatornähe und rotieren entsprechend schnell.
Deine Schlussfolgerung ist nicht richtig. Äquatornähe bedeutet nicht zwangsläufig schnelle Rotation. Die Halpha-Linie ist eine Rekombinationslinie und wird in der ausgedehnten Äquatorscheibe erzeugt (bis zu 20 Sternradien Ausdehnung). Sie rotiert wegen der geringen Blau- bzw. Rotverschiebung relativ langsam. Das hast Du ja auch mit 60 und 100 km/s gemessen.
Quote:
Nach außen hin nimmt Geschwindigkeit und Dichte/Helligkeit ab.
Das ist bei Kepplerbahnen einer Plasmascheibe anzunehmen.

Gruß, Thomas


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 Post subject: Re: Kap Dra
PostPosted: 14. May 2019, 23:24:37 PM 
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Neueinsteiger

Joined: 24. December 2018, 09:41:40 AM
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Hallo Christian und Thomas,

vielen Dank für Euer Feedback und Erklärungen. Die Aufnahme der Spektren ist der leichtere Teil, die korrekte Interpretation ist ungleich schwerer. Da liegt noch einiges an Lesestoff vor mir. :)

Ich habe heute in der "BAA Spectroscopy Database" für künftige Langzeitbeobachtungen einige Kandidaten gefunden. Speziell die BE-Sterne sind spannend und immer für Überraschungen gut. Ich hätte vor einem Jahr nie gedacht, dass mich mal "Striche und Zacken" so begeistern können.

Viele Grüße

Hermann


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 Post subject: Re: Kap Dra
PostPosted: 15. May 2019, 11:47:45 AM 
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Nutzer
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Dear Hermann,

To know what observing each night for Be stars, you can use Aras beam :
http://arasbeam.free.fr/spip.php?page=b ... t2&lang=en

In green :recently observed (no more data need)
In yellow : to observed soon
in Red : to be observed immediately
in purple : intensive observation required

At this time in Bess database we have some "call for observations" for this list of Be Stars:
- Kap Dra
- Tet Crb
- V442 And
- Pi Aqr
- 66 Oph

Your spectra are welcome and you can of course upload your spectra in bess data base :
http://basebe.obspm.fr/basebe/


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 Post subject: Re: Kap Dra
PostPosted: 15. May 2019, 13:42:52 PM 
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Hallo Hermann,

diese V/R-Aufspaltung sieht man sehr deutlich auch in der Hbeta-Linie. Anbei frühere Messungen von mir. Wobei die Hbeta-Emission der Be-Sternscheibe inmitten eines ausgedehnten photosphärischen Absorptionstroges liegt. Die Hgamma-Linie ist dagegen in reiner Absorption (nicht im Bild gezeigt). Offensichtlich sind die physikalischen Bedingungen in der Gasscheibe so, dass Halpha sehr stark emittiert, Hbeta weniger und Hgamma gar nicht.


Attachments:
Vergleiche.jpg
Vergleiche.jpg [ 31.81 KiB | Viewed 1946 times ]

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Herzliche Grüße / best regards

Lothar

https://lotharschanne.wordpress.com/
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 Post subject: Re: Kap Dra
PostPosted: 15. May 2019, 14:04:49 PM 
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Hi Olivier! That's a very attractive and motivating website. However, I can't find additional information about the full data analysis procedure. The only respective information I find is this:

"The main objective for ArasBeAm program is to detect and track outbursts. We also want to record any short, mid and long term evolutions in Belmer lines profile - mainly Ha."


After submitting spectra, what will be done with them? Who analyzes them? Will they be used for physical analysis? Will it end in a publication? If yes, who will do that? What is the benefit for the observers?

I find some projects under "News" but the above questions remain unanswered. Especially the questions of co-authorship is crucial because I have often experienced a completely arbitrary and non-satisfactory handling of this point.

Cheers, Thomas


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 Post subject: Re: Kap Dra
PostPosted: 15. May 2019, 14:14:30 PM 
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Nur für einen ersten Eindruck: Die Balmer-Serie hat folgende Übergangsenergien

Halpha = 1,89 eV ~ 21.000 Kelvin
Hbeta = 2,55 eV ~ 28.000 Kelvin
Hgamma = 2,98 eV ~ 33.000 Kelvin

Außerdem kommen Emissionen vom Wind und Absorptionen von Photosphäre. Daraus kann man zwanglos ableiten, dass Halpha in den kühlen, äußeren Regionen der Sternscheibe erzeugt wird und Hgamma ziemlich nah am Stern. Hbeta liegt dazwischen aber immer noch nah an oder in der Photosphäre.


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 Post subject: Re: Kap Dra
PostPosted: 15. May 2019, 14:54:40 PM 
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Hallo Hermann,
noch stärkere Emissionen zeigt der Be-Stern gam Cas. Da sind sowohl in den drei Balmerlinien alpha, beta und gamma auch in der HeI6678 Emissionen zu sehen (aus der Gasscheibe, siehe Anhang). Aber auch viele Fe-Linien sind in schwacher Emission (siehe Anhang, Linien um 640 nm) und HeI5876 (siehe Anhang).
Ebenfalls ein interessantes Beobachtungsobjekt!


Attachments:
gamCas_20090318_14p20_nor.gif
gamCas_20090318_14p20_nor.gif [ 23.66 KiB | Viewed 1925 times ]
gamCas20071115_17p80_nr.png
gamCas20071115_17p80_nr.png [ 21.85 KiB | Viewed 1925 times ]
Auswertung alle Linien.png
Auswertung alle Linien.png [ 7.66 KiB | Viewed 1925 times ]

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Herzliche Grüße / best regards

Lothar

https://lotharschanne.wordpress.com/
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 Post subject: Re: Kap Dra
PostPosted: 16. May 2019, 09:26:56 AM 
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Neueinsteiger

Joined: 24. December 2018, 09:41:40 AM
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Hallo Olivier, Lothar & Thomas,

danke ! Sehr informative Feedbacks. Werde ich mir für künftige Beobachtungen auf jeden Fall vormerken.

Gruß
Hermann


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 Post subject: Re: Kap Dra
PostPosted: 16. May 2019, 20:58:34 PM 
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Hi Thomas
Quote:
After submitting spectra, what will be done with them? Who analyzes them? Will they be used for physical analysis? Will it end in a publication? If yes, who will do that? What is the benefit for the observers?

I find some projects under "News" but the above questions remain unanswered. Especially the questions of co-authorship is crucial because I have often experienced a completely arbitrary and non-satisfactory handling of this point.
ARAS BeAM is just a tool for amateurs to identify which Be Stars should be monitored. (The decision is driven by professionals who operate the BeSS database where the spectra can be found.
http://basebe.obspm.fr
To date there have been 78 publications from 2007-2019 which use data from the BeSS database. The list can be found under "publications" on the BeSS database website and the conditions for publication and crediting contributors are very specific and described in detail on the website.

"If data extracted from BeSS are used in scientific publications, please mention the sentence:
"This work has made use of the BeSS database, operated at LESIA, Observatoire de Meudon, France: http://basebe.obspm.fr"

Moreover, when you use many spectra obtained by the same person or if one spectrum provided important information for your work, we strongly encourage you to welcome him/her as a co-author of your publication. It is sufficient to thank in your publication observers which provided less spectra. Proper acknowledgments of the work of observers insures that observers will keep their motivation and continue to feed BeSS with their data"

I am not aware of any complaints from contributors to BeSS.

The same system is also used for the BAA and ARAS databases

Robin


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 Post subject: Re: Kap Dra
PostPosted: 16. May 2019, 21:13:03 PM 
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I encourage all amateurs to place their spectra in publicly accessible long term databases (After publication if you like to keep them private before) so they can perhaps be used by future generations. Even if you put them in other databases, for example ARAS, I can recommend also adding them to the BAA database to protect them long term
https://britastro.org/specdb/
The BAA has 180 years of variable star observations. It is now doing the same for amateur spectra.

Cheers
Robin


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 Post subject: Re: Kap Dra
PostPosted: 16. May 2019, 21:18:50 PM 
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Thank you, Robin, that explains the issue in sufficient detail.
Quote:
I am not aware of any complaints from contributors to BeSS.
In 2014 the Teide WR134/5/7 campaign delivered data of Nova Del to the database. They were published in A&A without respective acknowledgements/co-authorship. So, it is not as straightforward as it should be.

Cheers, Thomas


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 Post subject: Re: Kap Dra
PostPosted: 17. May 2019, 01:56:33 AM 
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Hi Thomas
Quote:
Thank you, Robin, that explains the issue in sufficient detail.
Quote:
I am not aware of any complaints from contributors to BeSS.
In 2014 the Teide WR134/5/7 campaign delivered data of Nova Del to the database. They were published in A&A without respective acknowledgements/co-authorship. So, it is not as straightforward as it should be.
I think it is unfair of you after 5 years to continue discourage anyone from contributing spectra to the BeSS or ARAS databases or campaigns on this basis. Nova Del was an ARAS campaign, not BeSS. The Convento group contribution was acknowledged in the paper though not the individual observers as the spectra were not individually attributed. (This was similar to the procedure used by AAVSO for example until recently). The authors of the ARAS paper acted in good faith and did not deliberately set out to exclude anyone from receiving credit. The procedure for acknowledgement has been clarified since then.

The Nova Del campaign was the largest amateur spectroscopic campaign ever run. It was very successful. It demonstrated how amateurs could react fast to a changing situation giving coverage that professionals could not achieve and a number of new amateurs started contributing to Pro-Am campaigns as a result. ARAS is now a very productive observing group as can be seen from the papers published using amateur data
http://www.spectro-aras.com/forum/viewforum.php?f=33


Cheers
Robin


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 Post subject: Re: Kap Dra
PostPosted: 17. May 2019, 07:33:01 AM 
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Hi Robin!

I don't think I discourage anybody else. As in all other areas, I would like to distribute a certain clarity. In particular I would like to point out potential or real problems to avoid them in the future. That should be in everyone's interest, right?. When we uploaded the data to BeSS at the time, my colleagues and I assumed that there was a reasonable appreciation, especially of our students at Teide. But that never happened. This is not good, especially if everyone finances the data supply with private money. These data were published by professionals under their name (not as „ARAS“) without sufficient appreciation. I had complained to them on behalf of all Teide team members, but of course the paper was already published. My respective emails remained unanswered.

If observers are not honored with their name (as in AAVSO) but only cursorily, then this should also be clear in advance. If I publish something, then I put ALL participants in the list of co-authors. Why? I show my appreciation and motivate further cooperation.

Yes, the Nova Del campaign was the largest amateur campaign ever and very successful. But this story remains in the memories of many participants. By the way, the Teide campaigns were organized by VdS and we wanted to support ARAS when we moved the telescope away from our own campaign targets. Nobody from ARAS or the Nova Del Pros even once said a word about this and about the missing acknowledgements in our forum. That's quite uncommon in the professional community. At least I don’t like that!

Once again, I don't want to attack anyone personally but point out potential problems to eliminate them in the future. Great, if that's already done. But discussions are important.

Cheers, Thomas


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 Post subject: Re: Kap Dra
PostPosted: 17. May 2019, 09:46:35 AM 
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PS: I worked for a few years with the professionals. I'm used to it that the term "criticism" has a positive connotation. So when I talk about the potential problems with database handling, it has nothing to do with "fairness". I'm not the judge, I'm just giving my opinion.


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 Post subject: Re: Kap Dra
PostPosted: 17. May 2019, 14:45:21 PM 
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Quote:
Thank you, Robin, that explains the issue in sufficient detail.
Quote:
I am not aware of any complaints from contributors to BeSS.
In 2014 the Teide WR134/5/7 campaign delivered data of Nova Del to the database. They were published in A&A without respective acknowledgements/co-authorship. So, it is not as straightforward as it should be.

Cheers, Thomas
Hi Thomas,

This is a perfect example of what is known as a "Straw Man" in English :roll:
https://en.wikipedia.org/wiki/Straw_man
I am not going to play your game any more today :)

Robin


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 Post subject: Re: Kap Dra
PostPosted: 17. May 2019, 15:22:15 PM 
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Yes, sometimes it is not easy to deal with critical questions.


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 Post subject: Re: Kap Dra
PostPosted: 21. May 2019, 12:28:34 PM 
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Hallo Hermann,

die Linie SiIII (4552) ist auch sehr interessant!

LG Siegfried


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 Post subject: Re: Kap Dra
PostPosted: 21. May 2019, 21:31:43 PM 
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Hello everybody,

I posted spectra of kap dra, 66 Oph, tet crb to Robert Klement who requested these observations on 30/03/19 no response to date !

I also posted spectra of kap dra attached to the BeSS validation team 3 weeks ago.

I am still waiting for feedback on what went wrong with the validation process at their end and how to resolve it ?

Regards,

Jack

Essex UK


Attachments:
Jack Martin_hd109387_2019_04_21T01.44.45_002_1D.png
Jack Martin_hd109387_2019_04_21T01.44.45_002_1D.png [ 29.22 KiB | Viewed 1557 times ]
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