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  • we're gonna talk about a star called Eater.

  • Carina Eat a Karina.

  • Yes.

  • Is that how it's pronounced?

  • That's how I pronounce it.

  • It is a star.

  • So the reason why it's called Eater is because it's in this Stella classifications scheme where you go through a consolation and you name the stars through the Greek alphabet.

  • Peter Letter of the Greek alphabet on green eye Because it's in the constellation of Carina, this is the chorus star in the sky.

  • By a long way, you don't mean call in the astronomy.

  • No, I mean calling the amazing since yes, it is truly astounding object, plus an outside chance it might kill us all.

  • So it's kind of good to know about.

  • It's a stall that's kind of right.

  • At the end of its life, there's a possibility it's gonna blow up possibilities already blown up.

  • Given that it's 7.5 1000 light years away, outside possibility that when it blows up it will create one of these gamma ray burst.

  • There's an even more outside possibility that that gamma ray bursts will be pointed directly the earth on.

  • When that gamma ray bursts hits the atmosphere, it will fry.

  • That's a popular story.

  • In fact, if you hunt around the Internet, you'll find that Corinne is gonna kill us all.

  • But actually it's not so for various reasons, firstly, almost certainly because of the nature of the object.

  • When this thing explode, it's not gonna produce a gamma ray burst on as you'll see from the geometry of it.

  • We're pretty sure that if there is a gamma ray burst, it won't be directed in our direction anyway, So it's not gonna kill us.

  • It will be pretty spectacular.

  • If it goes supernova, then it will be as bright as the full moon when it goes for, you know, a year or so afterwards.

  • So, actually, we're pretty spectacular sight in the sky when it goes, but it's really not gonna kill us.

  • The gun's probably not loaded, and even if the gun is loaded, it's not pointed at exactly.

  • So.

  • So we're not looking down.

  • The barrel will be fine.

  • We don't know.

  • A huge amount about this story is actually quite hard to figure out exactly what's going on.

  • And so observation.

  • It's hard to see what's going on.

  • Theoretically, we really don't understand these very last stages of a star's life particularly well.

  • So the short answer is yes, it could go off tomorrow.

  • It could go off in 50,000 years time, and we really don't know which.

  • So this is what this thing looks like.

  • So it really is pretty spectacular looking object.

  • When you point the Hubble Space Telescope at it on, the reasons for this weird structure will come through in a second, but the stars coming somewhere down in the middle there.

  • It's a slightly weird star because actually, it's very variable.

  • And so it was when it was first documented in the 18th century, it was sort of a naked I object.

  • Then, in the 19th century, very briefly became incredibly bright.

  • It became the second brightest star in the sky for a while, second only to serious, and then it faded out of out of naked eye.

  • So I entirely faded down again.

  • And so there is around a lot, so it's clearly there's something pretty dramatic going on thing with stars.

  • Usually they sit around for millions billions of years not doing anything very much.

  • The fact that this thing is vary on a time scale of years tells you that something pretty dramatic going on it.

  • All this other stuff You could see that the thing you can see around it is called the Homunculus Nebula.

  • Because it's supposed to look like a little person really see it myself.

  • But there we go.

  • And what?

  • I don't know homunculus.

  • That means it's a small person a ll That stuff you see around it.

  • This homunculus nebula is actually associated with these massive frightening that hand in about 18 40.

  • What's thought will happen.

  • This is Star almost exploded.

  • At that point, it almost went supernova and in the process.

  • So there's a very massive star in the middle there.

  • It weighs about 120 times the mass of the sun and in about 18 40 it through through off about 20 or 30 times the mass of the sun.

  • Good fraction of its total mass got thrown out into space.

  • And what you're seeing there is that debris kind of expanding away from the star could easily have exploded entirely at that point.

  • But it looks like it just lost about 30% of its mass.

  • Of that point.

  • Is this a common occurrence for stars to have a sort of A I'm not quite a near death experience.

  • I think it's the only one we really know about.

  • I mean, this is it is very massive stars That's more than 100 times the mass of the sun.

  • They're quite rare, and this is the closest example it's about.

  • It's only about 7.5 1000 light years away, which actually sounds a long way.

  • But but actually, for stars that massive, this is a relatively nearby example of it because they really are very few and far between.

  • What happens next?

  • Does it does it?

  • Does it get another cracker, or is it missed its chance to go out in a blaze of glory?

  • Our understanding of these late stages of stellar evolution or really sufficiently poor that we just don't know, probably will blow up at some point.

  • That's a further complication, which will come to, which is, Actually it's no a single star.

  • It's got a companion, so it's another star around it.

  • So the main stories about 100 times the mass of the sun there's another little star, which is only about 20 or 30 times the mass of the sun in orbit around it.

  • And in fact, these two stars will see it quite closely, interacting, which further complicates our understanding of what's going on.

  • This is a two dimensional view of this star on.

  • You can kind of in for the three dimensional shape, sort of just by looking at it.

  • But the neat thing that's been recently done is some astronomers have figured out how to turn this two dimensional picture into a three dimensional picture, essentially by using the expansion of the of the lobes.

  • Because this material's all flying out, you can actually measure the speed at which the different bits of expanding by looking at the Doppler shift in the light that's being emitted on.

  • So you look at a particular spectral line, something that should be occurring at a particular wavelength, and you should see how much it's blue shifted all red shifted to figure out how fast it's moving and by making some assumptions about how the things expanding you can then turn that speed into the third dimension in space, essentially because the further you are away from the star, the force that things are moving so If you see something moving very fast, it's probably a long way from the star.

  • You see things moving more slowly.

  • It's kind of closer to the stars.

  • That sort of gives you that third dimension and that allows you with it.

  • Looks fairly clever analysis to turn this into a three dimensional picture of what this thing looks like.

  • These guys published a paper about this.

  • So here's their three dimensional model of automatics that expanding groups pair of blobs looked like They also produced a three D cat model for what they've done, and so that anyone who's got a three D printer can go out and print their own.

  • So we put our install go on received.

  • So it is a three D printed versions.

  • I went to our guys in the University of Nottingham.

  • There's a group who do a thing called Additive manufacturing, which is basically figuring out really clever things to do with three D printers.

  • Hello.

  • This is not their kind of their main business.

  • They can three d print anything pretty much unlike you know, the usual three D printers.

  • They can actually put in lots of different materials as well, so they actually printed this out for me.

  • Entertaining.

  • Um, this is a star printed.

  • Entertain him based on that three d model of what this exploding star looks like, I have to say this is far beneath their dignity to do this kind of thing that actually they could do the most amazing stuff.

  • Their ultimate ambition, these guys is they want a three d print, a mobile phone, which works as soon as you take it out of the printer.

  • So that's the kind of level of ambition.

  • So you can see this is really not pushing their technology, particularly try and see if we can orient it kind of the same way as it is in.

  • It's gonna be tough, you know?

  • What were you looking at?

  • Things from It's kind of something like that, I think from where you are.

  • Thank you.

  • So the main things you can see are those kind of two lobes, presumably the there's an access to the start of something to do with its direction of rotation.

  • Probably there was a kind of disk of material around the star, which stopped it from expanding in that direction, and therefore the expanded towards the poles of the star is too low, as you can see, sticking out all the results of that explosion out along the poles of the star.

  • But you can see there's a lot of other structures.

  • Well, there were these little There's a little dimple in the end on this strange kind of groove channel in the end here and the other thing that they really studied, really?

  • For the first time of these two bits sticking out the side which turned out to be, might be telling us something while the fundamental about the nature of the explosion.

  • And this is the first time they've really been able to see this the sort of three dimensional structure of these strange wing sticking out to the sign they printed out in plastic on Dhe being ableto look at it, they actually using this lots of uses for this.

  • This actually allows you to study things in a way that they're not being studied before.

  • They're also very useful AIDS.

  • For example, if you're trying to explain astronomy to blind people being able to produce three dimensional models of things and so they become much more tactile, so they're useful from an educational perspective as well.

  • But actually you can learn things about the structure of something just by being able to look at it, really, in three dimensions.

  • It's so much more somehow more real when you have a little three dimensional model of something rather than just looking even animated on the computer screen.

  • Thea other thing That's interesting about this object it is.

  • It is a binary star that was actually only discovered about 10 or 15 years ago on the way that the easy way that we know it's a buy and restore is because actually things very in this thing in a periodic way every 5.5 years, for example, this object produces a sudden burst of X rays on, so it's being monitored over quite a long period of time.

  • And they monitored serious these X ray bursts on what's happening there is you got these two massive stars.

  • No one remembers about 110 solar masses, about probably 20 or 30 solar masses.

  • Each of those stars is actually hazardous of strong stellar winds, which only throwing particles off its outer layers off the whole time.

  • And it's all up there on a very the low mess.

  • One lower mess.

  • One is on a very eccentric orbit around the higher mess one, and so they kind of orbit around each other and and you've got the winds coming off.

  • So the wind from one smacks into the wind from the other.

  • And it was very intense interaction where the winds collide with each other form shocks get heated up to very high temperatures in the mid X rays.

  • Obviously, when that thing reaches close to its closest approach, the small star approaches.

  • The biggest are you get a sudden burst of X rays cause this is something very strong interaction between the two.

  • And what happens is that the little A star has a lower density but higher speed wind, which kind of clears out a cavity in the big bigger star.

  • So you could see that this is sort of strange.

  • Little spiral structure appears.

  • But the more interesting thing is that most of the time the structure looks something like this, that the little stars kind of cleared out a region of the biggest are it looks like Pac Man eating a power pill.

  • So exactly, and But the interesting thing is that how how wide the Pac man's jaws open here, which is about 121 130 degrees.

  • And the direction in which this opening is pointing because if we go back to this little model for a second, there were these two lobes sticking out to the sides on the angle between them is about 130 degrees, and in fact, the direction in which they're pointing is that exactly the same as the direction of that opening.

  • If you enjoy this video, you will almost certainly love Deep Sky Videos, our dedicated astronomy channel, where we focus in depth on various astronomical objects and in between, show you around some of the world's best telescopes.

  • Check it out.

  • There's a link on the screen and in the video description.

we're gonna talk about a star called Eater.

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驚くべきイータカリナエ - 60のシンボル (The Amazing Eta Carinae - Sixty Symbols)

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    林宜悉 に公開 2021 年 01 月 14 日
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