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Betelgeuse, getting more red year by year


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Convinced that year by year the old girl is getting redder and redder. I recall observing it 30 years ago and for sure it was red then but nowhere near as much as now and since last year gotten redder still. Pointed it out to my wife and she agrees. What do you guys think?

Rgds, Steve

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I havent observed the universe through a telescope for more than a year so I can't say I noticed any change :)

But! If it's changing it sure could mean interesting times ahead, imagine that thing going supernova! We would see that in daylight!

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Convinced that year by year the old girl is getting redder and redder. I recall observing it 30 years ago and for sure it was red then but nowhere near as much as now and since last year gotten redder still. Pointed it out to my wife and she agrees. What do you guys think?

Rgds, Steve

Sent from my iPhone using Tapatalk

Don't forget that everything you see gets warmer ( redder /more yellow) as you get older and your natural lenses age. I had my lenses replaced last year and the difference between each eye where one eye was modded and the other off the shelf, was quite dramatic. Both eyeballs have been modded now, and the colours are so much nicer (cooler)

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Don't forget that everything you see gets warmer ( redder /more yellow) as you get older and your natural lenses age. I had my lenses replaced last year and the difference between each eye where one eye was modded and the other off the shelf, was quite dramatic. Both eyeballs have been modded now, and the colours are so much nicer (cooler)

Yep, that thought had occurred to me as well ! Maybe I am just an old gi* and that explains it ! :)

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I had a look at Belelgeuse last night as the cloud was in and out and spoilt the view of M42 that I wanted, and Belelgeuse is one of those Stars that just begs attention..and the other half loved it too. It certainly was redder than i recall from years ago, but not so dramatically that it could not be accounted for by atmospheric seeing and perhaps my aging eyes.

However I do know that in the last 18 months there have been new images of Betelgeuse taken that shows the nebular surrounding it to be bigger than thought, highly mobile and increasing in size, and spectroscopic analysis indicates that this outer nebula of ejected material, which is several times the mass of the Sun, is made up primarily of silicates and Alumina dust, that could be causing an apparent reddening of the star as a result of scattering in the same way that dust in the atmosphere causes clouds to appear a pinky red. Of course it could also be that there is more dust in the atmosphere here and simply causing a slight enhancement of the redness of the star...however i think this not overly likely as I don't think anyone has reported a similar reddening of other red stars..

There is an article on the nebula surrounding Betelgeuse here, and here is an image of the "Flames of Betelgeuse from the latest research

Image Credit: ESO/P. Kervella)

110623085844-large.jpg

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Isnt Beetlejuice a variable star?. I have seen it ruby red once.............quite amazing. Most of the time its kind of orange to me. During the Leonids shower the other night,it was salmon coloured. I guess its mostly down to local conditions/transparency.

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Isnt Beetlejuice a variable star?. I have seen it ruby red once.............quite amazing. Most of the time its kind of orange to me. During the Leonids shower the other night,it was salmon coloured. I guess its mostly down to local conditions/transparency.

Yep, it's a semiregular variable with a period of almost 6 years. It's also got the largest range of variability for a star of its magnitude - around 1 magnitude in total.

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All these guys that say they want it to become a Supernova I'd disagree. It'd leave a horrible hole and a familiar nighttime friend would be gone. Hopefully another star will get blown up instead (not the sun though please) :)

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All these guys that say they want it to become a Supernova I'd disagree. It'd leave a horrible hole and a familiar nighttime friend would be gone. Hopefully another star will get blown up instead (not the sun though please) :)

My money is on Eta Carinae. Southern hemisphere unfortunately though.

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Yep, it's a semiregular variable with a period of almost 6 years. It's also got the largest range of variability for a star of its magnitude - around 1 magnitude in total.

It has also shrunk in size by 15% since 1993. If it hasnt alread imploded, it wont take that much longer to do so.

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It has also shrunk in size by 15% since 1993. If it hasnt alread imploded, it wont take that much longer to do so.

On a galactic time scale, no it won't. On a human time scale it could be a million years yet. The envelopes of red supergiants are highly unstable things and vary immensely with occasional outbursts.

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Isnt Beetlejuice a variable star?. I have seen it ruby red once.............quite amazing. Most of the time its kind of orange to me. During the Leonids shower the other night,it was salmon coloured. I guess its mostly down to local conditions/transparency.

Paul, you are right, Betelgeuse is classed as a semiregular Pulsating Red Supergiant and the variability was first noticed by Sir John Herschel in 1836, he actually published these findings in his book Outlines of Astronomy (1849). Over the years since then Betelgeuse has been seen to rise as high as Magnitude +0.4, thus rivaling Rigel. At the low point in the pulsation cycle the star can sink as low as +1.2.

Betelgeuse may vary by as much as 60% in physical size during this period, changing in size from about the size of the orbit of mars at Minimum to the size of the orbit of Jupiter at Maximum. It is the 7th brightest star in the northern hemisphere and one of the brightest in it's class. At Minimum it is some 7500 times the brightness of the Sun and at the peak of the pulsation it is up to 14000 times brighter.

Recent Hipparchos measurements have pinned it's distance down to 425 light years and at that distance the star would be the brightest in the sky by a long way if we were able to see in UV or IR, at the moment the star is spectral type M5 and it only radiates around 13-15% of it's total energy output in visible light. There are debates about the stars actual mass, and estimates range from 20 times the Sun to more than 40. So far little work has been done on the alleged two companion stars, one thought to orbit at about 5AU from the outer envelope and the other about 40-50AU away. Some research on these would pin down Betelgeuse's mass more accurately and allow us to make some better determinations about the star, namely, will it make a planetary nebula or go bang as a supernova..the mass is critical to answering this question because in recent years there has been some evidence to show that supergiant stars can shed enough mass to avoid the supernova path, but the bottom limit of this is current unclear..although we do know the final star mass must exceed 8 solar masses to be sure of a bang!

It would be intriguing for us for the star to explode as a supernova, I suspect that at 425 light years we would be safe from any real detrimental effects, but i suspect that for a short time it would seriously spoil the night sky in the Orion/Taurus/Canis Major region of the sky.

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Really interesting facts there ^^^^^^^^^. I didnt know its distance had been finally pinned down. I thought it was 466 LY away. No one really was too sure. Amazing to think only 13-15% of its energy is radiated out as visible light.

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Paul, here is a good article from the ESO on the subject of Betelgeuse

Here is a good article, well research paper, on the subject of the distance to Betelgeuse.

Here is some more research

I think we have to take the distance to Betelgeuse with a pinch of salt and there certainly seems to be some discussion going on. Clearly the pulsations of the star and variability of the parsec sized outer envelope are making things very difficult but the maximum distance would be no more than about 500Ly and the minimum, based on the recent Hipparchos data revisions seems to be about 390...the majority seem to pin this down to between 420-460LY...

Nice and clear isn't it!1

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