Betelgeuse to nova ? Not a hope - so don't hold your breaths for it happening anytime soon !

We've recently had a thread stating that some scientists believe that Betelgeuse is possibly on the verge of going nova.
And just a short time ago, a new thread where people are believing that there has been a sudden deepening in Betelgeuse's visible colour to a deep orange/red.

As a result, there is a growing belief (hope ?) that Betelgeuse is about to provide us with an incomparable spectacle of a 2nd sun in the heavens, and possibly banish night for a few weeks.


Yes, it's true that Astronomers have detected a recent diminishing of Betelgeuse's diameter on the order of approximately 15%.
But what does this mean regarding the stars remaining life expectation estimate ? Isn't this a sure sign that somethings afoot and the star has begun to shrink ? Doesn't this shrinkage mean the end is imminent ?


Unfortunately, I'm going to have to dash cold water on the hopes of those holding their collective breaths for a "Death Star" type of explosion happening anytime soon. Personally I believe we'll all be long gone before Betelgeuse kicks the proverbial stellar bucket !

So why do I feel this way ? Answers pretty simple and easily available if you're prepared to do a little bit of online digging around and research ... yes, what a horrible word is research ... but it's how we hope to separate the wheat from the chaff ... the truth from the fantasy.


Ok, lets start with a bit of stellar nuclear physics, shall we ?

All stars are created essentially in areas of space where hydrogen is available in huge quantities. Over time, and under the influence of gravity, large quantities of hydrogen begin to collapse inwards forming spheres. As the hydrogen continues to inexorably collapse inwards under gravity, the pressure inside the sphere begins to rise dramatically until a critical pressure point is reached. When this point is reached, the electrons orbiting the hydrogen atoms are stripped away and the exposed hydrogen nuclei violently forced together with sufficient energy to overcome their normal repulsive tendencies. At this point, 2 hydrogen nuclei are fused together to form an atom of helium with a large surplus of energy being generated ... and the new star self-ignites.

This energy surplus is radiated outwards from the star and into space in the form of light, heat, x-rays, neutrino's, etc. Normally this outward bound pressure would blow the star apart but at some point, the pressure of the outward energy/particle flow exactly matches the ongoing tendency for gravity to pull the stellar material further inwards towards the stars center and a balance is achieved between explosion and compression and the star becomes stable ... neither shrinking or expanding.

This stability lasts for many millions of years (normally).

Ok, so this is essentially how Betelgeuse came into existence.

Now for many millions of years, Betelgeuse has been busy converting hydrogen into helium, shining away into the universe and managing a balancing act between exploding and collapsing.
In fact, thats exactly what our own sun is doing this very moment !

Everything is fine until a critical point is reached when the supply of available hydrogen begins to run out for Betelgeuse, At that point there is more helium than hydrogen within the star and energy production begins to decrease.
Once this happens, the relentless crushing forces of gravity momentarily gain the upper hand and begins to once more compress the material of the star towards it's center.

This new round of collapse does not continue because in a very short period of time, the pressure has once again risen even higher than before and is now powerful enough to start burning (fuse) helium atoms with a tremendous amount of new energy release. The amount of energy now being released is sufficient to prevent any further collapse of Betelgeuse and the star once more enters a relatively stable period in its lifespan.

Where before hydrogen was being fused into only helium, the switch to helium fusing is generating many heavier elements on the periodical table such as lithium, carbon, oxygen, nitrogen, etc.


It's being reported that Betelgeuse has shrunk in diameter about 15%, and is following the scenario of what is expected to happen when the supply of hydrogen begins to run out. One would tend to assume that Betelgeuse is now at the point where it's beginning to fuse not only it's remaining hydrogen but also helium as it's power generation source.

However, a star like Betelgeuse will not exhaust it's helium supply in the foreseeable short or long term future and will continue in a relatively stable state.

But what happens when even Betelgeuse's helium supply begins to run out ? Will it nova then ?
Unfortunately not even then (and we hear a sigh of disappointment amongst the waiting crowd) ... at least not immediately.

The reason being that when the helium begins to run out and again outward energy production falls below the limit to maintain stability, Betelgeuse will once more begin to collapse under gravity, and pressures will begin to rise enormously again until a point is reached at which even heavier elements like carbon will begin to fuse and release energy and stability regained temporarily for millenia to come.

In fact, element fusing within Betelgeuse can continue all the way up to iron and still generate surplus outward energy.
But beyond iron, more energy is required for fusion then is released and when that point is reached, gravity becomes the ultimate winner and Betelgeuse goes out in a final awe-inspiring burst of light and radiation.


And this is exactly why I don't believe Betelgeuse will be producing any kind of fireworks for millenia to come.

BEETLEJUICE BEETLEJUICE BEETLEJUICE!

andddd thats 200 posts! woohoo

Great post! Lots of info, facts, etc. Good to have in these discussions.

My only bone with your assertion of it being safe from supernova for a long time to come is that its fate entirely depends upon its mass, which is something that is not well understood yet. Its size can be deceiving in estimating its mass; this relationship between mass and size is one of the things which could indicate to us exactly how close it is to collapsing. And further, even if it is less massive than we believe (and therefore less likely to be anything impressive), we have been recently surprised by supernova explosions that were much larger than the Chandrasekhar limit would allow for, so it could still be as impressive as expected, or even more so.

While I agree that it is not statistically likely for it to go supernova within our lifetimes (as is everything else really interesting, LOL) I do not agree that we can say that it won't with any great degree of accuracy---hence why the top astronomers are not making that assertion today. They agree that it's not likely, but not impossible, and therefore always a great subject of further research.

Guess it's back to watching Dancing With the Stars for me

But seriously, that's an excellent post and I agree with yourself and 00nunya00 in that you've both raised some very valid and interesting points.

Always a pleasure when I can learn something new and "factual" from an ATS thread - unfortunately such threads are few and far between

S & F for the good work.

yes that was a great explanation of a stars life, i feel smarter after reading it.

BUUUUUUTTTT..........

how do you know its not already fusing iron?
or almost done fusing iron for that matter...

maybe this is its final red shine and now its gonna BOOM!!!

i can be hopeful if i want, dont burst my bubble

oh yeah, good informational post.

s&f

Originally posted by iSHRED
yes that was a great explanation of a stars life, i feel smarter after reading it.

BUUUUUUTTTT..........

how do you know its not already fusing iron?
or almost done fusing iron for that matter...

maybe this is its final red shine and now its gonna BOOM!!!

i can be hopeful if i want, dont burst my bubble

Hahahaha ... ok, ok ... Betelguese is currently on it's last legs and fusing iron

Seriously though, you raise a very valid point and one I didn't think of. There's absolutely no reason it couldn't be doing just that.

However, even if fusing iron started recently with the observed 15% diameter collapse, I'd guess Betelguese still has a good few hundred years left in her/him ! So again, long after I'm gone

Here's an article on Discovery News that says there won't be a betelgeuse supernova next year, in fact, these things aren't this accurately predictable. The article states that the author of the doomsday nova scenario added some fantasy to an existing article from last year
news.discovery.com...

reply to post by tauristercus


You nailed it.

The only thing I can add is a size comparrisson to give people an idea of just how large the star is and therefore how much material needs to be consumed at each stage...



864 900 000 miles in diameter, give or take. Although the immense sizes are hard to grasp, look at it this way; Jupiter is 741 000 000 miles from our Sun.

Most of the planets in our solar system would orbit INSIDE this star.

Thats ALOT of space for fuel.

Originally posted by GypsK
Here's an article on Discovery News that says there won't be a betelgeuse supernova next year, in fact, these things aren't this accurately predictable. The article states that the author of the doomsday nova scenario added some fantasy to an existing article from last year
news.discovery.com...

Good find and thanks

Guess nothing beats beefing up some boring old science report with a bit of destruction on a stellar scale to improve sales and circulation.
The positive side is that it's made many more people a little bit more aware of the sky than would have otherwise been ... any excuse for a bit of unexpected education is always a good thing

Originally posted by [davinci]
reply to post by tauristercus

 

You nailed it.

The only thing I can add is a size comparrisson to give people an idea of just how large the star is and therefore how much material needs to be consumed at each stage...

I knew that Betelgeuse was huge compared to our own sun but wow, that Youtube clip sure puts it into perspective.
And to think that giant Betelgeuse is considered small compared to some other stars !

Excellent find

Not to piss on your bonfire or anything but I'll take this thread just like I take any other thread regarding this matter.

As a grain of salt.

Betelgeuse is 640 light years away, so whatever data astronomers in the most advanced observatories have is over 640 years old.

However, you can have a star (no pun intended) for the info and effort that you put forth in creating this thread.

Originally posted by muse7
Betelgeuse is 640 light years away, so whatever data astronomers in the most advanced observatories have is over 640 years old.

Absolutely true.

However given that stars burn for billions of years, 640 years is statistically insignificant.

The good news is that Rigel (Orion's bright blue foot) could go off any time.

Nice post tauristercus, as always.

reply to post by tauristercus


Damn you and your positive, research lead opinions this is not the stuff of ATS, we want doom and gloom and the Apocalypse ASAP. Worrying about these super nova possibilities is like worrying about Yellowstone, if it happens, it happens there is nothing we as a species can do except hopefully survive the after effects. A gama ray busts could be on its way as we speak and either it is instant death or a slow painful death. I dont understand why some members round here are obsessed with the end, almost as if they welcome it, people must have crappy lives when they want the collapse of society or the end of all things

reply to post by [davinci]


Once again, you're making the same mistake as the OP----confusing diameter with MASS. Diameter does not indicate how much fuel is in there, nor how much is left.

I still have not seen my mass vs size issue addressed.

reply to post by [davinci]



Except when it comes to this poster's point----that it is very hard to get accurate data from this star, or indeed any star, because it's not like we can get right up to it. Everything we know is from far-off observation, and is subject to radical change because at these distances, it's hard to know for sure.

reply to post by tauristercus


Yeah, when I first read the article in some science blog about the possibility that Betelgeuse might go Nova I was really excited...untill I got to the end of it and it said that it could happen anytime from tomorrow, to a *thousand* years from now! LMAO!!! Basically its 'a big to do about nothing' IMHO. I guess they are only mentioning it now because "it would be really cool if" it happened around 2012.....but yeah...there is extremely little chance of that. Not to mention that according to how far away Betelgeuse is (I can't remember, off the top of my head) it may have happened already. For instance if its 10 light years away, and we see it happen tomorrow, then that means that it actually happened ten years ago. (not that this would really dampen its cool factor, but it is still interesting to think about)
* I can't remember exactly how long the article said...but it was a large number of years...at LEAST a thousand.*

Good thread.

But it still remains a fact that Betelgeuse is in his last stadium of life. Nobody knows when it's going to blow, it could be tomorrow, it could also be somewhere within the next 1.000.000 years...

Betelgeuse is already old for its size class and is expected to explode relatively soon compared to its age.[32] Solving the riddle of mass-loss will be the key to knowing when a supernova might occur, an event expected anytime in the next million years, with some speculation it could even occur in the next millennium.[34][90][91] Supporting this hypothesis are a number of unusual features that have been observed in the interstellar medium of the Orion Molecular Cloud Complex, which suggest that there have been multiple supernova explosions in the recent past.[73] Betelgeuse's suspected birthplace in the Orion OB1 Association is the probable location for such supernovae. Since the oldest subgroup in the association has an approximate age of 12 million years, the more massive stars likely had sufficient time to evolve to this stage. Also, because runaway stars are believed to be caused by supernova explosions, there is strong evidence that OB stars μ Columbae, AE Aurigae and 53 Arietis all originated with such an explosion in Ori OB1 2.2, 2.7 and 4.9 million years ago.[73]

At its current distance from Earth, such a supernova explosion would be the brightest recorded, outshining the Moon in the night sky and becoming easily visible in broad daylight.[32] Professor J. Craig Wheeler of The University of Texas at Austin predicts the supernova will emit 1053 ergs of neutrinos, which will pass through the star's hydrogen envelope in around an hour, then reach the solar system several centuries later. Since its rotational axis is not pointed toward the Earth, Betelgeuse's supernova is unlikely to send a gamma ray burst in the direction of Earth large enough to damage ecosystems.[91] The flash of ultraviolet radiation from the explosion will likely be weaker than the ultraviolet output of the Sun. The supernova could brighten to an apparent magnitude of −12 over a two-week period, then remain at that intensity for 2 to 3 months before rapidly dimming. The year following the explosion, radioactive decay of cobalt to iron will dominate emission from the supernova remnant, and the resulting gamma rays will be blocked by the expanding envelope of hydrogen. If the neutron star remnant becomes a pulsar, then it could produce gamma rays for thousands of years.[92]

en.wikipedia.org...

Just came across this article indicating that Betelguese may have a life expectancy still of around 1000 years ... give or take.
This estimate is based on the possibility that Betelguese may have already burned through all the lighter elements and is now fusing carbon.

Although Betelgeuse is only around six million years old,[1] some regard the star's current variability as suggesting that it is already in the carbon burning phase of its life cycle, and will therefore undergo a supernova explosion at some time in the next thousand years or so.

Again, supports my belief that we're going to miss the spectacle by a long margin ... unfortunately