23June2022: H alpha prominence spectral analysis

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p_zetner
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23June2022: H alpha prominence spectral analysis

Post by p_zetner »

Hi Everyone.

Warren's spectacular animation of the huge NW filaprom on the 23rd showed a lot of complex motion.
viewtopic.php?t=36774

Since I was imaging with my SHG on the same day, I thought I would take a look at the prominence spectrum to see if there was any sign of interesting spectral signature of this motion. Here is the result, presented as a montage of 5 hydrogen alpha spectra (images along the left side). The right side images are spectroheliograms with a yellow line indicating the slice of solar disk along which the corresponding spectrum was measured. The red boxes map the portion of the spectrum enclosed to the corresponding length of yellow line in the spectroheliogram. A velocity scale is indicated on the spectrum column of the montage. This is the velocity associated with a Doppler shift from the H alpha line centre.
Halpha_spectra_montage_cropped_proc.jpg
Halpha_spectra_montage_cropped_proc.jpg (205.26 KiB) Viewed 501 times

I was a bit disappointed that there was not much exciting action observable in the spectra. In the past, I've been able to observe very jagged emission line profiles associated with complex prominence motions. See, for example: viewtopic.php?t=12329

In the present case, there is a persistent central absorption core in all of the prom spectra. Since the prom was relatively "low lying" with respect to the limb, this might indicate absorption by the spicule forest between the observer and the prom. The absorption by the intervening spicules would lead to the observed effect since the wider emission profile of the prominence would then be partially masked near the line core. There is a relatively peculiar result visible in image #5 where the spectrum shows two "doughnut" emission shapes within the H absorption profile. These doughnut features actually correspond to the footpoints of the prom as shown in the corresponding spectroheliogram. A bit of a puzzle, which I'm still chewing on!

Cheers.
Peter


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Re: 23June2022: H alpha prominence spectral analysis

Post by Montana »

A fantastic study Peter, but I must admit I'm not quite sure what I am looking at. Am I right in thinking that as the spectra in the red boxes have moved to the left there is some blue shift?

Alexandra


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Re: 23June2022: H alpha prominence spectral analysis

Post by marktownley »

Interesting analysis.


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Re: 23June2022: H alpha prominence spectral analysis

Post by Carbon60 »

Very interesting, Peter....Science...boom....and I was just happy to have been able to create a spectrum :lol: :lol:

Stu.


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Re: 23June2022: H alpha prominence spectral analysis

Post by p_zetner »

Thanks for the feedback Alexandra, Mark and Stu.
Alexandra, I will work on a better graphic to help explain the observations and post it as soon as I get the chance.
Cheers.
Peter


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