AG Dra brightening

Information about outbursts of eruptive stars, Be activity, ...
Francois Teyssier
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Re: AG Dra brightening

Post by Francois Teyssier »

Update of Raman OVI equivalent width
The V curve in green (inversed scale)
AGDra_OVI.PNG
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François
umberto sollecchia
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Re: AG Dra brightening

Post by umberto sollecchia »

Bonjour à tous, voici ma contribution à cette symbiotique .
Profilo AG Dra.png
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Comparison.png
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Sincèrement.
Umberto
Joan Guarro Flo
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Re: AG Dra brightening

Post by Joan Guarro Flo »

AG Dra, in the night 2016 07 16.
J. Guarro
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Joan Guarro Flo
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Re: AG Dra brightening

Post by Joan Guarro Flo »

Hi,

AG Dra on the night 2017 04 07.

Cheers, Joan.
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Francois Teyssier
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Re: AG Dra brightening

Post by Francois Teyssier »

A full commented spectrum, using Tim's PlotSpectra
Taken during last outburst (cool outburst), so Raman OVI very weak
agdra_20160423_890_commented.png
François
Forrest Sims
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Re: AG Dra brightening

Post by Forrest Sims »

Here is a commented (ignoring the Balmer lines to reduce clutter) spectrum using PlotSpectra of AG Dra from last night. Maybe someone could enlighten me on the significant lines to look for and how to interpret the strength or weakness of these lines as compared to François spectrum in outburst?
Thanks!
Forrest
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Christian Buil
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Re: AG Dra brightening

Post by Christian Buil »

Part of a VHIRES-MO spectrum (R=48000) + C11 telescope taken last night:

Raman O IV

Image

Halpha

Image

He I

Image

He II

Image

Christian Buil
Francois Teyssier
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Re: AG Dra brightening

Post by Francois Teyssier »

Hi Woody

The giant of AG Dra is a K0-K3 giant of low metallicity. This is the reason why Fe lines do not appear

At low resolution, what can we do?

Measure Hb and HeII 4686
Let K = 0.534 * F(HeII)/F(Hb)
The temperature of the hot object can be estimated: T = 19.38*K^1/2 + 5.13 (in 10000 K unit)
This is a simplified Iijima's formula (1981), derived from Zanstra method

The ratio between HeI singlets and triplets (for instance 6678 and 5876) is a valuable indication of the electronic density

The flux of Raman OVI lines 6830 7085 (Raman scattering of O VI λ1032, 1038 A photons off neutral hydrogen) allows amateurs to "see" the farUV
The évolution of the flux of these lines will depend of the type of outburst ("cool" : they will nearly desappear "hot" : remain bright)
Interesting : the ratio F(6830)/F(7085). See Shore &al. (2010) : https://arxiv.org/abs/0912.1890

At higher resolution : lines profiles, radial velocity of the RG, ratio between the bue and red part of Raman OVI lines ...

Look at: http://www.astronomie-amateur.fr/Docume ... CE2016.pdf


All the best

François
Christian Buil
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Re: AG Dra brightening

Post by Christian Buil »

Comparison of 11/04 and 14/04 observations of AG Peg (Halpha). No very significant variation (the telluric are removed for a better comparison) :

Image

Christian Buil
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