Betelgeuse (Star) is Shrinking

You've all seen the bright star Betelgeuse on Orion's right shoulder no doubt, but did you know that it has been steadily shrinking? This could be indicative of it going super-nova in the near future, which would be quite and unbelievable show, so fingers crossed.

Here's the article about it from Berkeley. Here's more on the subject from New Scientist.

(By the way, this is a few weeks old, but interesting nonetheless).

Futurism

It would be spectacular if that happened. Is it possible that it's already exploded and we just haven't seen it due to it's distance? (Speed of light etc.)

Futurism

Futurism wrote: »

It would be spectacular if that happened. Is it possible that it's already exploded and we just haven't seen it due to it's distance? (Speed of light etc.)

Yah, definitely. It's 640 light years away, meaning that if it happened now we wouldn't know until 2649. It could have conceivably happened within the last five or so decades. It's a long shot, but it would be the most amazing celestial sight that we could wish to see; although, afterwards, Orion wouldn't be the beautiful sight that it is now: it missing a shoulder and all.

Futurism

I'll remain optimistic. Hopefully in our lifetime, it will happen.

TheManWho

Do we have any way of knowing if it has happened already, like gravitational anomalies on nearby bodies or other clues. For instance if it went supernova 639 years ago, would we have no idea up until the moment we see it.

TheManWho

TheManWho wrote: »

Do we have any way of knowing if it has happened already, like gravitational anomalies on nearby bodies or other clues. For instance if it went supernova 639 years ago, would we have no idea up until the moment we see it.

Well, that depends on general relativity being correct (and it seems to be). General relativity states that gravity travels at the speed of light. So, basically, we wouldn't know until the light hit us, i.e. 640 years. There is no way to get around this limitation (i.e. placing a probe at the edge of the solar system etc., as the information can travel at a max speed: the speed of light).

The speed of gravity hasn't been measured experimentally (as far as I'm aware), it has only been measured via astronomical observations. If gravity does indeed travel faster than light, then Einstein's general relativity would be proven wrong; but that would mean that we could possibly know about it before 640 years.

Tzetze

TheManWho wrote: »

Do we have any way of knowing if it has happened already, like gravitational anomalies on nearby bodies or other clues. For instance if it went supernova 639 years ago, would we have no idea up until the moment we see it.

Gravitational waves are subject to the same speed limit as everything else in the universe - light speed. The information can't reach us any more quickly, and with our current technological prowess, there's no way for us to get to the information any more quickly either. Of course, if we could travel at 99% c, we could cut the interception delay time by half, but that's not likely to happen anytime soon.

Ron DMC

Ok, I'm trying to imagine the scales here, stars are really massive so if it does/did go boom, I'd expect the explosion to be so large that it would be visible for ages. We're talking at least days, but probably weeks or even months.

Or am I being silly and would it just be one big flash and disappear?

mike65

If it went bang (sorry its almost certainly already gone bang the light hasn't reached us) the effect would be visible for months and would light the night sky like a full moon.

Ron DMC

mike65 wrote: »

If it went bang (sorry its almost certainly already gone bang the light hasn't reached us) the effect would be visible for months and would light the night sky like a full moon.

Oh, wow, now that really sounds excellent.

Here's hoping the light gets here within our lifetimes so...

mike65

I probably should have added a *Subject to correction and clarification which indeed could be the forum slogan I suspect.

Yah, it would become the second brightest object in the sky (after the sun; and I think I've read that it would be brighter than a full moon). So, it would be quite a sight. The good thing is that it's at a safe distance, too. Any closer (i.e. 2/3 hundred light years), and life on Earth would have a hard time.

Here's (PDF) a very interesting article (it's more of a paper, really) on the implications of the Sun going supernova on Earth (that won't happen, though).

Tzetze

It has happened in recent (relatively) history when the star that became the Crab Nebula went supernova in 1054.

wiki wrote:

Recent analysis of historical records have found that the supernova that created the Crab Nebula probably appeared in April or early May, rising to its maximum brightness of between apparent magnitude −7 and −4.5 (brighter than everything in the night sky except the Moon) by July. The supernova was visible to the naked eye for about two years after its first observation. Thanks to the recorded observations of Far Eastern and Middle Eastern astronomers of 1054, Crab Nebula became the first astronomical object recognized as being connected to a supernova explosion.

Ostrom

Dont NASA have a satellite monitoring gamma bursts from suspected hypernovas? Can supernovas produce emissions of similar magnitude?

mike65

Just to put the possible size of the bang into context

AlmightyCushion

-JammyDodger- wrote: »

Yah, it would become the second brightest object in the sky (after the sun; and I think I've read that it would be brighter than a full moon). So, it would be quite a sight. The good thing is that it's at a safe distance, too. Any closer (i.e. 2/3 hundred light years), and life on Earth would have a hard time.

That's pretty cool. How long would it be visible for at that brightness?

AlmightyCushion

AlmightyCushion wrote: »

That's pretty cool. How long would it be visible for at that brightness?

As far as I know, it would be visible for several months, maybe even over a year. It'd orginally be very bright, but it would slowly fade over the course of time and eventually it would be impossible to see with the naked eye.

AlmightyCushion

-JammyDodger- wrote: »

As far as I know, it would be visible for several months, maybe even over a year. It'd orginally be very bright, but it would slowly fade over the course of time and eventually it would be impossible to see with the naked eye.

I really hope this happens (and reaches us) in our lifetime. It would be some sight to behold.

TheManWho

I was just watching a documentary on constelations and this star was mentioned when they discussed orion. Michu Kaku gave the briefest of summeries about why this star is interesting and could have already exploded. So thank you Expand Your Horizons, I have never in my life been able to nod in agreement to an astronomy documentary.

Also, this star is apparently pronounced Beetle-Juice, which I never would have gathered from the spelling.

AlmightyCushion

TheManWho wrote: »

Also, this star is apparently pronounced Beetle-Juice, which I never would have gathered from the spelling.

I was wondering about that.

Yah, it's an odd name alright. It's derived from Arabic I think.

I read earlier today that its radius is shrinking at ~480 miles per hour, which is an extremely high rate when you think about it.

Here's another article talking about its shrinking.

Here's another article with a very interesting podcast in which an astronomer talks about the phenomenon.

Edit: I just found this "paper" on what the consequences of a nearby supernova would be. It's a very good read, but it's a tad bit technical.

Ostrom

Are brief pastings from jstor/academic search premier ok with citation?

ASP is great - it links to popular astronomy magazines aswell as journals within searches - for people like myself with limited technical knowledge.

Orion should be visible at a reasonable hour from Oct-Nov?

efla

efla wrote: »

Are brief pastings from jstor/academic search premier ok with citation?

Are they freely available on the internet, or does the website which supplies the paper (JSTOR, for example), require a subscription to view their journals?

Ostrom

-JammyDodger- wrote: »

Are they freely available on the internet, or does the website which supplies the paper (JSTOR, for example), require a subscription to view their journals?

Some of them link back to publications such as Astronomy, and Sky and Telescope - ASP archives HTML copies, so I'm assuming the content is freely available. Probably best not to copy the article, but I assume citations are ok?

efla

efla wrote: »

Some of them link back to publications such as Astronomy, and Sky and Telescope - ASP archives HTML copies, so I'm assuming the content is freely available. Probably best not to copy the article, but I assume citations are ok?

I'd assume so, too. I've asked the powers that be what their stance on this is, so if they deem it inappropriate, we can always remove the extracts that you've provided.

If you want to post anything, work away (with citations). Just make sure that it comes from a legitimate website/archive site.

Ostrom

Thanks, anyone with ASP access can recover these by searching for the title (non technical)

Betelgeuse Making Waves, Sky & Telescope; Mar2009, Vol. 117 Issue 3, p16

Berman, Bob, 2009.Betelgeuse: the next banana split? Astronomy; Feb2009, Vol. 37 Issue 2, p16

Betelgeuse: Star in a Shell. Sky & Telescope; Feb2008, Vol. 115 Issue 2, p18

eso.org

Here's a bit more on this that was published today, if anybody's interested (you can click on the photos for larger views).

eso.org wrote:

Using different state-of-the-art techniques on ESO's Very Large Telescope, two independent teams of astronomers have obtained the sharpest ever views of the supergiant star Betelgeuse. They show that the star has a vast plume of gas almost as large as our Solar System and a gigantic bubble boiling on its surface. These discoveries provide important clues to help explain how these mammoths shed material at such a tremendous rate.

A plume on Betelgeuse
(Artist's Impression)

A close look at Betelgeuse

Betelgeuse in Orion
(with annotations)

AA plume on Betelgeuse
(artist's impression with annotations)

Zoom in on Betelgeuse

Betelgeuse — the second brightest star in the constellation of Orion (the Hunter) — is a red supergiant, one of the biggest stars known, and almost 1000 times larger than our Sun. It is also one of the most luminous stars known, emitting more light than 100 000 Suns. Such extreme properties foretell the demise of a short-lived stellar king. With an age of only a few million years, Betelgeuse is already nearing the end of its life and is soon doomed to explode as a supernova. When it does, the supernova should be seen easily from Earth, even in broad daylight.

Red supergiants still hold several unsolved mysteries. One of them is just how these behemoths shed such tremendous quantities of material — about the mass of the Sun — in only 10 000 years. Two teams of astronomers have used ESO’s Very Large Telescope (VLT) and the most advanced technologies to take a closer look at the gigantic star. Their combined work suggests that an answer to the long-open mass-loss question may well be at hand.

The first team used the adaptive optics instrument, NACO, combined with a so-called “lucky imaging” technique, to obtain the sharpest ever image of Betelgeuse, even with Earth’s turbulent, image-distorting atmosphere in the way. With lucky imaging, only the very sharpest exposures are chosen and then combined to form an image much sharper than a single, longer exposure would be.

The resulting NACO images almost reach the theoretical limit of sharpness attainable for an 8-metre telescope. The resolution is as fine as 37 milliarcseconds, which is roughly the size of a tennis ball on the International Space Station (ISS), as seen from the ground.

“Thanks to these outstanding images, we have detected a large plume of gas extending into space from the surface of Betelgeuse,” says Pierre Kervella from the Paris Observatory, who led the team. The plume extends to at least six times the diameter of the star, corresponding to the distance between the Sun and Neptune.

“This is a clear indication that the whole outer shell of the star is not shedding matter evenly in all directions,” adds Kervella. Two mechanisms could explain this asymmetry. One assumes that the mass loss occurs above the polar caps of the giant star, possibly because of its rotation. The other possibility is that such a plume is generated above large-scale gas motions inside the star, known as convection — similar to the circulation of water heated in a pot.

To arrive at a solution, astronomers needed to probe the behemoth in still finer detail. To do this Keiichi Ohnaka from the Max Planck Institute for Radio Astronomy in Bonn, Germany, and his colleagues used interferometry. With the AMBER instrument on ESO’s Very Large Telescope Interferometer, which combines the light from three 1.8-metre Auxiliary Telescopes of the VLT, the astronomers obtained observations as sharp as those of a giant, virtual 48-metre telescope. With such superb resolution, the astronomers were able to detect indirectly details four times finer still than the amazing NACO images had already allowed (in other words, the size of a marble on the ISS, as seen from the ground).

“Our AMBER observations are the sharpest observations of any kind ever made of Betelgeuse. Moreover, we detected how the gas is moving in different areas of Betelgeuse’s surface ― the first time this has been done for a star other than the Sun”, says Ohnaka.

The AMBER observations revealed that the gas in Betelgeuse's atmosphere is moving vigorously up and down, and that these bubbles are as large as the supergiant star itself. Their unrivalled observations have led the astronomers to propose that these large-scale gas motions roiling under Betelgeuse’s red surface are behind the ejection of the massive plume into space.

Link to the article on eso.org.

jumpguy

Wow! That'd be amazing. I hope it happens in our lifetime. But isn't it possible it could become a black hole?

EurekAlert.org

Here's a bit more info on what was posted two posts above, for whoever is interested:

Link to EurekAlert.org article.

EurekAlert.org wrote:

An international team of astronomers, led by Keiichi Ohnaka at the Max Planck Institute for Radio Astronomy (MPIfR) in Bonn, has made the most high resolution images of a dying giant star to date. For the first time they could show how the gas is moving in different areas over the surface of a distant star. This was made possible by combining three 1.8 metre telescopes as an interferometer, giving the astronomers the resolving power of a virtual, gigantic 48 metre telescope. Using the ESO VLT Interferometer in Chile, they discovered that the gas in the dying star's atmosphere is vigorously moving up and down, but the size of such "convection cell or bubble" is as large as the star itself. These colossal bubbles are a key for pushing material out of the star's atmosphere into space, before the star explodes as a supernova. (Astronomy & Astrophysics, 2009, in press).

When one looks up at the clear night sky in winter, it is easy to spot a bright, orange star on the shoulder of the constellation Orion (the Hunter) even in light-flooded large cities. This is the star Betelgeuse. It is a gigantic star, which is so huge as to almost reach the orbit of Jupiter, swallowing the inner planets Mercury, Venus, Earth, and Mars, when placed at the centre of our solar system. It is also glaringly bright, emitting 100 000 times more light than the Sun. Betelgeuse is a so-called red supergiant and approaching the end of its short life of several million years. Red supergiants shed a large amount of material made of various molecules and dust, which are recycled for the next generation of stars and planets possibly like the Earth. Betelgeuse is losing material equivalent to the Earth's mass every year.

How do such giant stars lose mass, which would normally be bound to the star by the gravitational pull? This is a long-standing mystery. The best way to tackle this issue is to observe the situation where the material is ejected from a star's surface, but this is a very challenging task. Although Betelgeuse is such a huge star, it looks like a mere reddish dot even with the today's largest, 8 - 10 metre telescopes, because the star is 640 light years away.

Therefore, astronomers need a special technique to overcome this problem. By combining two or more telescopes as a so-called interferometer, astronomers can achieve a much higher resolution than provided with individual telescopes. The Very Large Telescope Interferometer (VLTI) on Cerro Paranal in Chile, operated by the European Southern Observatory (ESO), is one of the world's largest interferometer. A team of astronomers in German, French, and Italian institutions observed Betelgeuse with the AMBER instrument operating at near-infrared wavelengths. The resolving power achieved with AMBER is so great that one can recognize a 1-Euro coin placed on the Brandenburg Gate in Berlin
from Bonn.

"Our AMBER observations mark the sharpest images ever made of Betelgeuse", says Keiichi Ohnaka at the MPIfR, the first author of the publication presenting the result. "And for the first time, we have spatially resolved the gas motion in the atmosphere of a star other than the Sun. Thus, we could observe how the gas is moving in different areas over the star's surface."

The AMBER observations have revealed that the gas in Betelgeuse's atmosphere is moving vigorously up and down. The size of these "bubbles" is also gigantic, as large as the supergiant star itself (that is, one bubble as large as the orbit of Mars is moving at some 40 000 km/h). While the origin of these bubbles is not yet entirely clear, the AMBER observations have shed new light on the question about how red supergiant stars lose mass: such colossal bubbles can expel the material from the surface of the star into space. It also means that the material is not spilling out in a quiet, ordered fashion, but is flung out more violently in arcs or clumps.

The death of the gigantic star, which is expected in the next few thousand to hundred thousand years, will be accompanied by cosmic fireworks known as a supernova like the famous SN1987A. However, as Betelgeuse is much closer to the Earth than SN1987A, the supernova can be clearly seen with the unaided eye, even in daylight.

tech77

-JammyDodger- wrote: »

Well, that depends on general relativity being correct (and it seems to be). General relativity states that gravity travels at the speed of light. So, basically, we wouldn't know until the light hit us, i.e. 640 years. There is no way to get around this limitation (i.e. placing a probe at the edge of the solar system etc., as the information can travel at a max speed: the speed of light).

The speed of gravity hasn't been measured experimentally (as far as I'm aware), it has only been measured via astronomical observations. If gravity does indeed travel faster than light, then Einstein's general relativity would be proven wrong; but that would mean that we could possibly know about it before 640 years.

That is genuinely fascinating- always intrigued me since i was a kid.
Makes me feel i shoulda done physics in college :P

Does that effectively place a kinda "causality barrier" (i just made that up, apologies) of 640 years between that part of the universe and ours.

Anything at all could be happening there and we're insulated from its effect for 640 years- that's crazy.
Or could there possibly be other mysterious links between that place and here.

Jammyc

Oh poor Ford Prefect is gona be devestated! lol

But seriously, this sounds incredible. Would love to see it.:D