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Old 26-07-2020, 10:32 PM
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Stonius (Markus)
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Join Date: Mar 2015
Location: Melbourne
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Does anyone know the cause of this periodic anomaly near the Keyhole Neb?

I've noticed this structure that repeats fairly regularly just below the keyhole nebula. Below is a crop of my photo, but it's not an artifact, as you'll see the same structures in other images posted on the web depending on how they've processed them.

It consists of 4 dark bars (and as many as 6, though the other two are not as clearly defined and therefore a bit 'iffy')

Given the Keyhole structure is about 7LY across (and assuming the structures are contiguous with the greater nebula) I'd make the bars as being about 3LY long, spaced about 3LY apart.

If you look just to the north at Hubble's view of the Mystic Mountain region, you can again see a periodicity in the jets of young stars. Of course, now I'm starting to look for it, I'm seeing periodic features everywhere -in other nebulae too, like in the below Hubble shot of the Lagoon Nebula.

We know that the solar wind from newly formed stars creates these bubble-like voids in the surrounding gas and dust. Perhaps this would suggest a cyclical phase in early star formation?

I'm speculating here, but perhaps some stars don't just switch on and 'start shining', but instead waver across the threshold of viability several times before they reach a stable state. A possible mechanism would be if the energy from fusion creates expansion that, together with the loss of density would serve to put the brakes on the fusion reaction temporarily until the star had cooled, become more dense and more matter had collected to kick start the process again. Perhaps this happens a few times until it can sustain the reaction?

Alternatively I guess the same thing could be caused by a polar jet from a rotating object, I suppose?

It's an interesting feature, I suppose, and not one I have noticed before, even though I've looked at that image a hundred times or more!


Cheers


Markus
Attached Thumbnails
Click for full-size image (Carinae Bars.jpg)
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Click for full-size image (Mystic Mountains.jpg)
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Click for full-size image (Lagoon.jpg)
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Last edited by Stonius; 27-07-2020 at 12:55 AM.
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