Betelgeuse's sandy gift

By Phil Plait | June 23, 2011 6:30 am

For one of the brightest stars in the sky, Betelgeuse still has some surprises up its sleeve. We’ve known for a couple of years it’s surrounded by a cloud of gas, but new observations show that nebula is far larger than previously thought!

[Click to enorionate.]

This new image is care of the Very Large Telescope, and shows a very deep and very high-resolution shot of Betelgeuse in the infrared. The inner black circle is the 2009 shot of the star and its surrounding gas — what we knew about before — and the big image shows all the gas around it just discovered. At the very center is a red circle indicating the actual size of Betelgeuse on this scale — it’s a red supergiant, and nearly two billion kilometers in diameter.

This structure is actually a wind of material blown off of the star itself. The exact mechanism behind this is unclear, though. Red supergiants are so big that gravity on their "surface" (they don’t really have a surface; they just kinda fade away into space) is very weak, and they can barely hold on to the material there. They are also incredibly luminous — Betelgeuse is 6000 trillion kilometers away, yet one of the brightest stars in the sky — so much so that the pressure of light is very strong. This pressure can lift material off the surface and blow it into space. It’s also known that Betelgeuse has gigantic convection cells bringing hot material from deep below up to the surface, and that’s part of this process as well.

Once the material is ejected it forms into dust grains: complex molecules including hydrocarbons. The astronomers doing this observation detected oxygen-rich dust in this nebula (PDF), which given the environment is most likely silica or alumina. Silica, also known as silicon dioxide, is the main constituent of sand and quartz! That’s the most common constituent in the Earth’s crust — over 60% by mass — and we think that a lot of the materials in the Earth’s crust actually formed in the winds of red giants and supergiants.

Think about that the next time you’re playing at a beach this summer. Billions of years ago, some now long-dead red star belched silicon dioxide into space, seeding a nearby nebula with materials… and this cloud collapsed to form our Sun and planets, with some of that interstellar silicon dioxide making up the sand under your feet.

Not to mention that a lot of that water you see in the ocean came from giant comets slamming into the Earth shortly after it formed. Does that make your heart pound, your blood race? Because the iron in your hemoglobin came from massive stars that exploded long ago. If that makes you smile, why, the calcium in your teeth most likely came from an entirely different kind of star that exploded eons ago as well.

We’re directly tied to stars like Betelgeuse.

And oh: while you’re at the beach, do me one more favor. Find a grain of sand, just a single grain about a millimeter on a side. Now give it to a friend, placing it on their outstretched finger. Walk about 40 meters away, turn around, and look at your friend. The grain of sand will be invisible to your eye, far too small to see. Yet at that distance, that grain of sand appears to be the same size as the entire image above of Betelgeuse.

And you thought you were just going to the beach.

Someday, Betelgeuse too will explode as a supernova. It will briefly become as bright as the Moon, then fade over months. The material we see here will get slammed by octillions of tons of gas moving outward 10,000 times faster than a rifle bullet, destroying it. And when it’s all done, our familiar constellation of Orion will be left without his right shoulder.

But it’s worth it. What planets will coaleasce, what suns will shine, what forms of life will one day arise from that material, and wonder which star it was to which they owe their existence?

Image credit: ESO/P. Kervella


Related posts:

Betelgeuse and 2012 (I posted a followup to this as well)
Is Betelgeuse about to blow?
Orion’s WISE head
Spotting Betelgeuse
Betelgeuse shocker

Comments (54)

  1. IVAN3MAN_AT_LARGE

    And when it’s all done, our familiar constellation of Orion will be left without his right shoulder.

    It could be worse: he could be without his ‘dagger’! ;-)

    […], what forms of life will one day arise from that material, and wonder which star it was to which they owe their existence?

    Unless they find religion and think that “God did it!”. :roll:

  2. Mike

    Say, “Betelgeuse! Betelgeuse! Betelgeuse!” and the star will get even bigger.

    Go ahead, make my millenium.

  3. Annalee

    I can’t even handle how big space is right now. It is BLOWING MY MIND.

  4. Very nice, and a wonderfully romantic conclusion. A hat tip, sir.

  5. Carey

    I think Betelgeuse may be my favorite star.

  6. RwFlynn

    The thought that I know Orion will be losing his shoulder makes me a bit sad. It’s strange. I know that generations (or evolutions) from now everything in the sky will be ultimately unrecognizable to our 21st century eyes, but knowing that one detail of Orion’s fate makes me feel oddly nostalgic.

  7. Messier Tidy Upper

    Superluminous news – Betelgeux surprises and delights us again! :-)

    Could that sand survive the coming supernova and form new worlds or will the radiation be too intensely destructive?

  8. Sharku

    This text reminds me of that line out of Babylon 5:

    “We are starstuff, we are the universe made manifest, trying to figure itself out. “

  9. Messier Tidy Upper

    @ ^ Sharku : Which line I believe originated first with Carl Sagan! ;-)

    Unless I’m mistaken which, yeah, could be the case.

  10. Messier Tidy Upper

    @ 3. Annalee : “I can’t even handle how big space is right now. It is BLOWING MY MIND.”

    Mine too. I love the sense of awe and wonder, the ‘numinous’* or “Sacre Noir”** to borrow a couple more of Carl Sagan’s descriptions.

    (What really blows my mind personally for some reason is star brightnesses – Procyon is seven times brighter than our Sun, Sirius twenty-five times, Arcturus two hundred and fifteen times brighter, Rigel nearly a million times and Eta Carinae five million times! Can you imagine something just twice as bright?)

    See :

    http://www.youtube.com/watch?v=HEheh1BH34Q

    &

    http://www.youtube.com/watch?v=2FwCMnyWZDg&annotation_id=annotation_208405&fmt=22&feature=iv

    for the scale of things from planets to stars to the whole universe. :-)

    (Betelgeuse stars at the 1 minute 20 secs mark on the second one.)

    See :

    http://stars.astro.illinois.edu/sow/betelgeuse.html

    For more info on Betelgeuse via the wonderful James Kaler’s Stars website. :-)

    —-

    * From Sagan’s novel Contact later made into the eponymous movie starring Jodie Foster.

    ** From Sagan’s non-fiction ‘Pale Blue Dot’ book. A play on ‘Sacre bleu’ literally french for “Sacred Blue.”

  11. Jonathan

    Elegant, poetic and beautiful science. What a wonderful wonderful way to start my day (yes, it’s 10:00)

    Thank you so much.

  12. Ohio Mike

    “Yet at that distance, that grain of sand appears to be the same size as the entire image above of Betelgeuse.”

    Could someone please rephrase this? I love relative comparisons, but can’t ‘get’ this one…

  13. Ian S

    @12 the grain of sand forty feet away covers the same angular distance across the sky as the entire field of view in the picture under discussion, which is to say that something unimaginable huge (a red supergiant and associated nebula) occupies a tiny tiny fraction of our sky, just imagine how many such wonders are available to view? and also how amazing is our technology that we can resolve such detail in such a tiny field of view…

  14. Andrew

    One of your most poetic posts. Loved it.

  15. Messier Tidy Upper

    @ 8. Sharku :

    Do you mean this :

    http://www.youtube.com/watch?v=3Vz5bl9GQp0

    scene? :-)

    Another one of my favourite speeches from Babylon-5 (LOVE That Show! :-D ) can be found here :

    http://www.youtube.com/watch?v=g4KVcV_rMwY

    While this :

    http://www.youtube.com/watch?v=iE9dEAx5Sgw

    is how Carl Sagan put things. :-)

  16. feh

    [i]”Someday, Betelgeuse too will explode as a supernova. It will briefly become as bright as the Moon, then fade over months.”[/i]

    Don’t get me wrong, nothing against Betelgeuse, but I wish this could happen in our lifetimes. Both, full moon and the Betelgeuse supernova high in the sky during early morning / evening would be an amazing and unforgettable sight.

  17. Messier Tidy Upper

    @ ^ Feh : I’ rather Eta Carinae went supernova in my lifetime than Betelguese or, for that matter, Antares. I like Orion and Scorpius as they are. :-)

  18. I am currently working with P. Kervella on Betelgeuse and Paris Observatory. Thank you for this wonderful article !

  19. John Baxter

    I must read headlines more carefully. “sandy beach” and “sandy belch” are not the same thing.

  20. Just FYI, I changed the post title. I had written the original title before finishing the post, and while writing decided to go the more poetic route. The title didn’t really reflect that. :)

  21. Beautiful. I love the shades of Shakespeare in your last lines there, Phil. “How many ages hence …?”

  22. ethanol

    I hate to be a pedant, but, well who am I kidding I love being a pedant. Phil said

    “Once the material is ejected it forms into dust grains: complex molecules including hydrocarbons”

    Since when are dust grains complex molecules? I would take a very complex molecule indeed to reach the size of a dust grain. I suppose he probably meant “dust grains composed of complex molecules including hydrocarbons” but this seems improbable as well. It seems unlikely that such a high temperature and oxygen-rich environment would condense out any form of reduced carbon, and I find no mention of hydrocarbons in the linked paper. Certainly hydrocarbon grains exist, but is this how they are formed? Otherwise, nice post.

  23. Matogatos

    Why does it sound so similar to Nuclear Fission

  24. Messier Tidy Upper

    @ ^ ethanol : Since when are dust grains complex molecules?

    Depends on the type of dust I suppose, no?

    @21. Phil Plait : Thanks – I much prefer the new title for this. Great write-up. :-)

    @19. Miguel M. : “I am currently working with P. Kervella on Betelgeuse and Paris Observatory. Thank you for this wonderful article!”

    Seconded by me. :-)

    Can you elaborate on your studies at all please? I’m curious – and, I must admit, a bit envious too.

    Working *on* Betelgeuse – it may be cool for a star but I imagine you’d need a pretty heat proof spacesuit still – and however did you travel there? ;-)

    [Runs for cover and sheepishly admits his own appalling grammar fails at times. The pedant in me just couldn’t resist.]

  25. M Tadano

    I’m sort of hoping that Betelgeuse actually blew up about the time Christopher Columbus was setting sail for the New World. I’m also hoping that the estimate I read of it’s distance from us of around 520 light years is also accurate. If, by some chance, both of those are true then we could actually see it blow in the not-too-distant future. THAT would be incredible!

  26. Robin Byron

    Very inspiring, Phil. Sad so few of us humans will read it.

    I’ve sent Dr Sagan’s Pale Blue Dot text to many, many people and never heard so much as a word in response. Perhaps I should have sent the video? I will never truly understand why such beautiful wisdom means so much to us and so little to them.

  27. Piper Wilson

    What does “enorionate” mean? I tried to look it up, but couldn’t find it. Is it a typo?

    Also, like OhioMike, I’m afraid I don’t understand the phrase “that grain of sand appears to be the same size as the entire image above of Betelgeuse. ”

    Would someone please explain?

  28. lqd

    I learned about Betelgeuse from Bob Berman’s excellent book “Secrets of the Night Sky”, and now I love staring at it on winter nights and thinking about how enormous and luminous it is. It’s hard to imagine.

    If Betelgeuse has no surface, how is it possible for it to have star spots? I know that several space telescopes have resolved star spots on Betelgeuse, and since these always appear on a star’s surface, it seems logical to me that Betelgeuse would have a definite “surface” where these spots would occur.

    Also, I’ve read that Betelgeuse has already begun fusing iron. Does anyone know if this is really true, and if so, how do we know?

    One more quick tidbit: Betelgeuse means “the armpit of the sheep” in Babylonian.

  29. angela

    OK – so I probably know too much about dust around Betelgeuse for my own good, but actually the dust is more likely to be glassy silicate based on the IR spectra (which for alpha Ori have been observed for appprox 40 yrs). And the composition is probably more like the stuff on black sand beaches nr volcanos than silica (although honestly, when it’s glassy its hard to tell, but pure silica does have a different spectral feature than olivines and pyroxenes even when glassy).

    Also – most iron comes from Type Ia supernovae – which are relatively low mass binaries, magnesium and silicon come from high mass exploding stars.

    This is a very cool observation tho!

  30. Pepijn

    This seems like an excellent moment to shamelessly plug this video I made, comparing the size of Betelgeuse to the Solar System:

    http://www.youtube.com/watch?v=zppa-Zkp74E

  31. Mike

    The gas and stuff is fascinating, but the thing that floors me every time is the size of that damn star. a 1 billion km radius… 1 BILLION (actually 1.18 according to wikipedia). It would swallow Jupiter whole and give Saturn a good roasting. And it’s still only a little more than half the radius of the largest known star.

    Good Gravy.

  32. QuietDesperation

    I think it’s a Dyson sphere gone wrong.

  33. IVAN3MAN_AT_LARGE

    Piper Wilson:

    What does “enorionate” mean? I tried to look it up, but couldn’t find it. Is it a typo?

    No, it’s not a typo (you must be new to this blog!); it’s just Dr. Phil Plait playing with words and being silly. What Phil means by “enorionate” is: to embiggen the image.

  34. Doug

    Is the Silicon coming from burning Neon or Oxygen? The Oxygen cycle is supposed to be short, on the order of months as I recall, after which the Silicon goes in hours followed by a big boom.

    Or is the Silicon just left over from some previous star?

  35. Thespis

    *clears throat, tunes up:*

    It’s a great BIG universe
    And we’re all really puny!
    We’re just tiny little specks
    About the size of Mickey Rooney!
    It’s big and black and inky!
    And we’re all small and dinky!
    It’s a big universe and it’s ours!

    -Yakko’s Universe, from the show Animaniacs (written by Randy Rogel)

  36. IVAN3MAN_AT_LARGE

    Piper Wilson:

    Also, like OhioMike, I’m afraid I don’t understand the phrase “that grain of sand appears to be the same size as the entire image above of Betelgeuse.”

    Would someone please explain?

    This should help: Angular diameter.

  37. David

    @29 Actually, lighter elements are being fused into iron. Once you get iron you can’t get any more energy from fusion. That’s what eventually leads to a type II supernova; when enough iron builds up in the core and it collapses and causes the explosion.

    @30 Actually it’s the other way around. Type Ia supernova consist of white dwarfs that grow too large and collapse and fuse lighter elements like carbon and oxygen and blow themselves up completely. These produce silicon and magnesium. Iron is not produced in these explosions. Iron comes from type II supernova explosions which are caused by high mass stars .

  38. HvP

    Ethanol said, “Since when are dust grains complex molecules? I would take a very complex molecule indeed to reach the size of a dust grain”

    Astronomers routinely refer to any complex molecule in space that can’t be described as a simple gas as “dust.” Keep in mind that this is the same group of scientists that term anything other than hydrogen or helium as “metals.”

  39. David

    Correction. iron is produced in type 1a supernovae but it comes from the decay of nickel-56 and cobalt-56.

  40. angela

    @David – the production of iron in things like Betelgeuse happen because of fusion – but they fusion products typically don;t get thrown out in the explosion because thy remain in the core that becames the neutron star. Whereas Type Ia supernova are responsible for thrhowing out the iron.

    @HvP – as someone who actually studies stardust I can assure you that not all of us refer to complex molecules as dust; It is one of my pet peeves that PAH molecules (polyaromatic hydrocarbons) get referred to as VSGs (very small grains) – they are molecules in gas phase – not solid state – and this affects spectral properties which is essentially our only diagnostic…

  41. Burdette

    When Betelgeuse finally does explode, it will be a wonderful sight for the people alive at the time…alas, the probability of it happening in our lifetime is pretty small…

  42. HvP

    Angela, I stand corrected and certainly defer to your experience in the matter :)

  43. Messier Tidy Upper

    @42. Burdette : When Betelgeuse finally does explode, it will be a wonderful sight for the people alive at the time…alas, the probability of it happening in our lifetime is pretty small…

    Maybe so but we’re actually statistically overdue for a visible supernova in our galaxy or so I gather. Doesn’t mean it will happen tonight but it will happen, eventually.

    Since the telescope’s invention we’ve been unlucky our Milky Way’s derth of supernovae but one is bound to happen sometime. Hopefully soon. :-)

    As long as it isn’t *too* bright and nearby of course! ;-)

  44. Nigel Depledge

    OK, so Ivan3man got there before me, but I think a little more can be added…

    Piper Wilson (28) said:

    What does “enorionate” mean? I tried to look it up, but couldn’t find it. Is it a typo?

    Phil is a master of neologisms. And he invents words sometimes, too ( ;-) ). Betelgeuse is a star in the constellation Orion, so to enorionate is to embiggen the picture (but only for something in Orion). It’s all perfectly cromulent.

    Also, like OhioMike, I’m afraid I don’t understand the phrase “that grain of sand appears to be the same size as the entire image above of Betelgeuse. ”

    Would someone please explain?

    You know how small things close up look as big as bigger things farther away? This phenomenon is the angular diameter that Ivan3man mentions.

    Think of it along these lines:
    If you go out on a clear night and observe the corner of Orion occupied by Betelgeuse, the part of the constellation that is included in the image above is a very small portion of the night sky. A similar proportion of your field of view would be occupied by a 1-mm sand grain viewed at a distance of 40 metres.

  45. Nigel Depledge

    David (38) said:

    @30 Actually it’s the other way around. Type Ia supernova consist of white dwarfs that grow too large and collapse and fuse lighter elements like carbon and oxygen and blow themselves up completely.

    Wait, what?

    I thought a type Ia was a white dwarf accumulating material from a companion star. When this material gets dense enough, it ignites in a short-lived fusion reaction of a very predictable brightness (hence these are used as “standard candles”). Is it or not really?

  46. Nigel Depledge

    MTU (44) said:

    . . . we’re actually statistically overdue . . .

    But do the stars know this?

  47. Piper Wilson

    @Ivan3man – Yes, I’m new.

    @Ivan3man & Nigel – Thank you both.

  48. realta fuar

    The phrase “that grain of sand appears to be the same size as the entire image above of Betelgeuse” appears to be nonsense. A grain of sand seen at a given distance has a defined angular diameter, while any image has any angular diameter one wishes, given what scale it’s displayed at and what distance it’s viewed from. (just saw where Ian S. above explained what the author apparently meant to say, which apparently was that the angular diameter of the grain of sand viewed from 40 meters is the same as the field of view of the image shown. That works out to be about 5 arc-seconds or about 1/360 the diameter of the full moon.
    Angela (s.?) above already corrected the other obvious mistakes in this post.

  49. Messier Tidy Upper

    @47. Nigel Depledge :

    MTU (44) said: “. . . we’re actually statistically overdue . . .”
    But do the stars know this?

    Hmm ..Good point, we’d better go tell them! ;-)

    @46. Nigel Depledge :

    David (38) said: “@30 Actually it’s the other way around. Type Ia supernova consist of white dwarfs that grow too large and collapse and fuse lighter elements like carbon and oxygen and blow themselves up completely.”
    Wait, what? I thought a type Ia was a white dwarf accumulating material from a companion star. When this material gets dense enough, it ignites in a short-lived fusion reaction of a very predictable brightness (hence these are used as “standard candles”). Is it or not really?

    As I understand it you’re both right! ;-) :-)

    Type Ia supernovae are indeed caused by white dwarf stars exploding after gaining too much material on their surfaces from stellar companions – or possibly from meregrs between white dwrafs and their binary partners.

    Yes, there are, so I gather, all supposed to be about the same brightness and ar ethsu used as “standard candles” because they all come from the same mass assuming the model where they get just enough to go over the Chandraseker limit then detonate is right. If I Recall Right, there are possible complications here – I think I read somewhere that a wite dwarf star *above* the supposedly forbidden mass limit has been discovered possibly managing this by spinning at a certian rate or something – and there are competing models of the SN Ia cause eg. mergers as well as accretion which the BA blogged about some time ago.

    But yeah, type Ia supernovae do totally destroy their stars – similiar events but less major events that do NOT do so are termed novae .

    Not sure of the source of confusuon really – you appear to be saying much the same things – unless I’m mistaken here which is always possible. :-)

  50. Messier Tidy Upper

    Supernovae (SN) classes in a nutshell as I understand it :

    Type Ia = white dwarfs picking up too much matter. Totally destroys the star.

    Type Ib & Ic = Wolf-Rayet Stars and perhaps also Luminous Blue Variables with their outer layers blown away via suffering core collapse when fusion finally fails. Leaves a neutron star or Black hole core remnant.

    Type II = Red (& blue) Supergiants with outer layers still intact being blown away via core collapse when fusion finally fails. Leaves a neutron star or Black hole core remnant.

    Pair-Instability SN = The most rarest and most massive stars of all esp. the theoretical Population III Stars (the first born and largest ever stars) and v. low metallicity hypergiants detonating when photons convert to electron-positron pairs and totally destroy the star.

    More info. on type Ia and other supernova here :

    http://en.wikipedia.org/wiki/Supernovae

    Via wikipedia.

    http://blogs.discovermagazine.com/80beats/2011/04/28/tychos-supernova-went-boom-after-slurping-up-some-of-its-neighbor/

    On one specific type Ia SN example in detail – Tycho’s supernovae.

    Plus the competing type Ia SN models here :

    http://blogs.discovermagazine.com/badastronomy/2010/02/18/dwarf-merging-makes-for-an-explosive-combo/

    as discussed by the BA back in Feb. last year with great spaceart illustrations and all! :-)

  51. It occurred to me only a few days ago that Betelgeuse is exactly in the mass range where things turn a bit odd regarding supernovae. SN in nearby galaxies, where the progenitor was imaged before in high-resolution imaging (by chance) have never turned out to originate from a red supergiant star with a mass between 16.5 M_s and 25 M_s, although there should have been a few, from a statistical point of view. See: http://arxiv.org/abs/1011.0203 There are different explanations, either the explosion takes place during a “blueward excursion”, or as a different SN type (which seems unlikely as there has never been a SN of this other type identified with a high-mass star), or there is no SN at all, just a silent collapse to a black hole.

    If this is correct, then it means that most probably, Betelgeuse will either not go supernova any time soon (because its not in a blueward excursion), or it will die in a silent collapse to a black hole, without SN. Well, we shall see, as nature has suprised us so many times. But still: if one day Betelgeuse just disapears from Orion without any SN, then now you know what happened…

  52. Nigel Depledge

    @ MTU – thanks for the info.

    I guess I never really realised that a Type Ia destroyed the star (none of the descriptions that I had read previously mentioned this aspect of it, so I just assumed it could happen several times over).

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