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paulastro

FEBRUARY 21ST - D-DAY FOR BETELGEUSE ?

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This could be a significant date in indicating if Betelgeuse is about to go supernova according to spaceweather.com.  

It's thought the dominant probable pulsation period of Betelgeuse is around 430 days, and if so around Feb 21st  its current mag should rise from its current low of +1.66 to around +0.9. 

So if the mag remains as it currently is,  we may have to get our sunglasses out when we go out at night at some time in the not too distant future!

I for one will be out around Feb 21st  doing some magnitude estimates - the results may indicate if something very significant may be about to happen :cool2:.

 

  Get the full story at:                https://spaceweather.com/

 

Betelgeuse is a highly evolved red supergiant--the type of star that could collapse and explode at any moment. Indeed, the dimming of Betelgeuse could be explained if the star has suddenly contracted to about 92% of its previous radius. But that's not the only possibility. Betelgeuse might be dimmed by a giant starspot--or maybe it is shrouded by an outburst of stardust from its own cool outer layers--or something else entirely. No one knows.

Answers might be forthcoming on Feb. 21st. Astronomers have long known that Betelgeuse is a variable star. It pulsates with many periods, as shown in this Fourier analysis of Betelgeuse's light curve:

fourier_strip.png
Above: A period analysis of 23 years (1995-2018) of Betelgeuse photometry. Credit: Peranso.

"This shows a dominant (probable pulsation) period of P = 430 days," note Guinan and colleague Richard Wasatonic in a recent Astronomical Telegram. Given this result, "the minimum brightness is expected on 21 (+/-7d) February 2020."

If Betelegeuse starts to bounce back on Feb. 21st, this whole episode might just be a deeper-than-average pulsation, and perhaps the supernova watch can be called off. However, notes Guinan, "even if the 430-day period is still working, this would indicate a minimum brightness near 0.9 mag--much brighter than the current value near 1.6 mag. So something very unusual is going on."

Stay tuned for updates as Feb. 21st approaches.

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Interesting info Paul. I confess I don't believe that a SN  is imminent, and suspect this is just a deep minimum in its variability. Quite possibly it is becoming more unstable but I'm sure it has a long way to go.

Question though, 21st Feb? Surely that may just be a minimum when it starts to brighten so would not really be a visually detectable change. It won't suddenly jump up to mag 0.9?

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Quite right Stu.  But, if it's all correct, then from this date it's worth keeping an eye on.  It would be quite something if you were observing it one night and it went supernova.  I know it's very unlikely, but it will happen sometime and someone will be the first to see it!  😃

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If you look back at AAVSO records (they go back to 1911) on Betelgeuse it's been dimmer than this occasionally,

 

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Well John, I am sort of lucky, so it may still be me who 'discovers' it when it finally blows its stack. :)

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It's a semi-regular variable, and quite an odd one at that. It's rotation rate is far higher than expected for a red supergiant, and it's nitrogen content is higher than normal. Both can be explained if Betelgeuse is a merger of two stars, where the companion of a massive star was swallowed as the more massive star turned giant. This would spin the star up and churn up nitrogen-rich material from the core into the outer layers, and simultaneously refuel the core with hydrogen. If this is correct, Betelgeuse should last a lot longer than standard estimates for the life of a red supergiant. 

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1 hour ago, paulastro said:

Betelgeuse is a highly evolved red supergiant--the type of star that could collapse and explode at any moment.

Take this line from the article quoted in the first post, you remove the hyperbole which now seems to be part of most of what is written online, that sentence would read something like this.

Betelgeuse is a highly evolved red supergiant the type of star that could collapse and explode some time in the next 1 million years.

 

 

Edited by Charles Kirk
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7 minutes ago, Charles Kirk said:

Take this line from the article quoted in the first post, you remove the hyperbole which now seems to be part of most of what is written online, that sentence would read something like this.

Betelgeuse is a highly evolved red supergiant the type of star that could collapse and explode some time in the next 1 million years.

 

 

And if you take the refuelling effect of the star merger model into account this becomes 8 million years. Time will tell

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Blimey, I didn't expect anyone to take is so seriously 😀.  Of course in any one persons lifetime the odds are it won't happen, and that will always be true, even in thousands of years time.  Mind you, it will happen in someone's life time - if there is anyone left alive to witness it!

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I think we have a habit of over complicating things.. either it will go SN or it won't in my life time, that's two options, therefore I make it 50/50... not bad odds tbh.. 😂😉

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Time for celestial fireworks if we are lucky enough 😁

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8 hours ago, paulastro said:

Well John, I am sort of lucky, so it may still be me who 'discovers' it when it finally blows its stack. :)

Hey there. There is a whole alternative live and disagreeable thread about The Big B going pop, and I have already called dibs on calling it ‘going bang’ although that was a couple of weeks ago.......

Seriously though, whatever your point of view, a very interesting subject and lots of information coming to the fore, which can only be a good thing.

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The big Fellah will pop in his own good time. He ate too much in his lifetime, and
the penalty for that is boom. All those fluctuations in his magnitude are simply him taking deep breaths from so much exertion.

By the way, how are all you weight watchers getting on. I remember you setting off on a regime of weight loss.
Hope you're all eating sensibly, and getting plenty of exercise.👍
Ron.

Edited by barkis

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First, thanks for posts like this. I do enjoy and appreciate learning from those with greater knowledge than I have. I think of life as one long school, me trying to learn everyday.

With that said,

Please humor my ignorance, but wow, it could have reduced in size by 92%?

That in itself is just mind boggling to me when I think of how large it has been. Could it possibly recover from such a large reduction in size?

I understand that as it burns heavier and heavier material, it changes, but would the extreme heat generated during this be enough to make rebound to its former size.

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It's not reduced 'by' 92%, it has reduced to 92% of it's original size.   If it had reduced 'by' 92% it would now only be 8% of its original size.

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5 hours ago, paulastro said:

It's not reduced 'by' 92%, it has reduced to 92% of it's original size.   If it had reduced 'by' 92% it would now only be 8% of its original size.

Okay, now I see where I misread. Makes much more sense to me now.

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23 hours ago, Dave Lloyd said:

Betelgeuse looks no brighter than Bellatrix tonight. 

That's rather Lestrange? 🤔😂

BellatrixLestrange.png

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Have a look on spaceweather.com - apparently Betelgeuse has become lopsided.  Interesting things going on.

Perhaps a big bang around February 21st isn't so outrageous.  In the unlikely event something does happen, I'll be saying 'told you so'  🤣

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Please excuse the ignorance, but when something like this does happen is it a fast event, perhaps happening in moments - like a 'bang' or will it occur over a longer time - if so over what sort of time?

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58 minutes ago, JOC said:

Please excuse the ignorance, but when something like this does happen is it a fast event, perhaps happening in moments - like a 'bang' or will it occur over a longer time - if so over what sort of time?

If you mean going supernova it depends on  which part you are talking  about.

The core colapse is very rapid seconds, this is followed by the colapse and rebound of the outer layers which is somewhat slower. The brigtning in the visible is due to the radio active decay of elements created during the "explosion". This can take a few days to peak depending on the type of supernova. 

Regards Andrew 

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As I sat outside looking at the stars with my jug of ale and binos last night, it appeared to me that Betelgeuse was considerably brighter than it has been recently. Whether it was my alcohol infused observing or the glowing horizon as Orion was dipping into the murk, I'm not sure. I could only judge that it was about the same brightness as nearby Procyon. 

Sorry to resurrect an old thread, with old news, but thought I would just comment that it does seem to be getting back to normal.

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