Ep. 560: Betelgeuse

Posted on Feb 19, 2020 in Astronomy, High Energy Physics, podcast, Stars, Stellar Evolution | 1 comment


You might be surprised to hear that we’ve never done an episode of Astronomy Cast featuring Betelgeuse. Well, good news, this is that episode. Let’s talk about the star, why it might be dimming, and what could happen if it explodes as a supernova.

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Fraser Cain:                 Astronomy Cast, Episode 560. Betelgeuse.

Pamela Gay:                Betelgeuse, Betelgeuse.

Fraser Cain:                 Welcome to Astronomy Cast. Welcome to Astronomy Cast. Our weekly facts-based journey through the cosmos where we help you understand not only what we know but how we know what we know. I’m Fraser Cain, publisher of Universe Today. With me, as always, is Pamela Pamela Gay, a senior scientist for the Planetary Science Institute and the Director of Cosmo Quest. Hey, Pamela. How are you doing?

Pamela Gay:                I am doing well. How are you doing, Fraser?

Fraser Cain:                 I am doing great. And I mentioned this in the preamble, but I just wanted to say this again, which is a huge congratulations to our good friend, Pamela Ian O’Neill, who just announced that he’s going to be working at NASA Jet Propulsion Lab in their media department. Ian is a terrific science journalist. One of the best in the business. And it’s a pretty good fit that he’s now working over at NASA. He was the editor for the Astronomical Society of the Pacific, Mercury. He has been a columnist for Discovery and Seeker. He did some work with us at Universe Today. And this is great. So, congratulations, Ian.

Pamela Gay:                And we’re gonna take the next two weeks off. I’m gonna call it Spring Break.

Fraser Cain:                 Yes.

Pamela Gay:                I’m not going anywhere. I’m just gonna be writing software, but you, sir, are going on a grand adventure.

Fraser Cain:                 Yeah. I’m going to Japan with my son. And there is – this is not work. This is literally just him – I said, “Where do you wanna go?” And he goes, “I wanna go to Japan.” And then I waited for cheap tickets to come around, and they did. And so, we’re off to Japan. Of course, we’re off to Japan when there’s a coronavirus, but we’ll take precautions. And it doesn’t look like it’s that bad there currently. So – and I can’t wait to see this place. I’ve wanted to go to Japan all my life. And to be able to do this is gonna be a lot of fun. So, I’ll definitely take pictures. Might visit a few spacey things, like the Japanese Space Agency, but this is about his trip, not my trip.

                                    All right. Well, see, you might be surprised to hear that we’ve never done an episode of Astronomy Cast featuring Betelgeuse. Well, good news. This is that episode. So, let’s talk about the star, why is might be dimming, and what could happen if it explodes as a supernova. I – it – I had to do a search before I actually wrote up my intro. And I think we suggested this one to – for Susie to put on the calendar. And like all of this time, we’ve talked about Orion, we’ve talked about the way stars die, and we’ve obviously mentioned Betelgeuse many times as a candidate for a new supernova but had never actually spent a whole episode on this one specific star.

                                    Well, obviously good timing on our part because it’s so interesting right now. So, what is Betelgeuse?

Pamela Gay:                It is a red, supergiant star that is visible to both the Northern and Southern Hemisphere. We have no hemispheric bias in choosing this star. It has evolved off the main sequence, which means it is no longer burning hydrogen in its very core. And it probably did this only about a million years ago. And now, it is systematically burning through heavier and heavier shells of elements, deep in its, well, many, many solar mass self as it hangs out, shining bright in the northern winter and the southern summer.

Fraser Cain:                 And it is – it is Orion’s right shoulder. I mean, when you look at it, it looks like it’s on the left, but if you were Orion and you were facing towards us, then it would his right shoulder.

Pamela Gay:                And there’s some fascinating history on its name, and I have to admit, I went down a little bit of a rabbit hole prepping for this episode. Its – its name is Arabic.

Fraser Cain:                 Yes.

Pamela Gay:                And over the years has probably been mistranscribed, so that there are those that believe that it translates as Orion’s armpit.

Fraser Cain:                 Right.

Pamela Gay:                And this could be caused by just dropping a little dot under one of the characters at that wrong moment in time. It probably has a much better name than Orion’s armpit. This is still up for a fair amount of discussion.

Fraser Cain:                 Well, actually, so one of our viewers, Rami Ahmed, who speaks Arabic, he’s saying that it is – the name comes from the Arabic [speaking Arabic], which literally means the armpit of the mighty hunter. So, that sounds better than Orion’s armpit.

Pamela Gay:                It – it’s –

Fraser Cain:                 The armpit of the mighty hunter.

Pamela Gay:                It’s true. It’s –

Fraser Cain:                 Yeah.

Pamela Gay:                – true.

Fraser Cain:                 And we – we’re gonna mispronounce it. And, of course, the hilarious thing is, is how people give us such a hard time because they’re expecting that it should be Beetlejuice.

Pamela Gay:                Yes.

Fraser Cain:                 But – and we tend to say Betelgeuse and that is – that’s a little bit of a holdover from, I think, the way they used to describe it before the movie came out.

Pamela Gay:                Yeah.

Fraser Cain:                 And the movie sort of has shifted it to beetle, but even that isn’t correct. So, maybe we can, after the fact, maybe get Susie to get maybe Rami or someone to do the proper Arabic pronunciation in the show and – so that then can serve as the – as sort of the standby.

Pamela Gay:                Yeah.

Fraser Cain:                 And I’ve heard a lot of people, like even Germans say, people are – say that, well, actually it’s a German word, but it’s not.

Pamela Gay:                No.

Fraser Cain:                 It’s an Arabic.

Pamela Gay:                Yes.

Fraser Cain:                 And it comes from – yeah. It has an Arabic root. So.

Pamela Gay:                And –

Fraser Cain:                 Anyway.

Pamela Gay:                Yeah.

Fraser Cain:                 So, we are gonna say Betelgeuse, and maybe even shift to Beetlejuice every now and then. Please, just bear with us.

Pamela Gay:                And however you choose to pronounce it, this isn’t an object that was strictly noted and observed by people living around the Mediterranean ocean. This is an object that – its variable and its brightness as all of us can currently go out and see. And this variability appears to have first been noted by the aborigines of Australia. It is a star that crops up in the lore of society after society, but the science, the awesome sauce science is why –

Fraser Cain:                 Yeah.

Pamela Gay:                – we’re here today. Because when you ask, which objects in the sky are most likely to go boom, this is one of the two. Eta Carinae is the other. It is strictly Southern Hemisphere, So, really Betelgeuse is the one we want so that all of us can enjoy the experience. And the problem is we don’t know when this is going to occur, but scientifically we’re pretty sure it’s not now.

Fraser Cain:                 Right.

Pamela Gay:                But you can hope to be wrong.

Fraser Cain:                 Yes. Yeah. So, it’s a random event. And we’ll talk about this a little bit about what’s going on and how we might know, but – so, I just wanna talk a bit about just what stage it is, what kind of star it is compared to, say, a star like our sun. So, how does this star compare to our sun?

Pamela Gay:                Radically different. Our sun is – because it is ours, it is used as the measuring stick by which we, well, measure everything else.

Fraser Cain:                 Right. It weighs one “the sun.”

Pamela Gay:                Exactly.

Fraser Cain:                 Yeah, it weighs exactly one “the sun.”

Pamela Gay:                Betelgeuse is estimated that when it was in the same evolutionary stage as our sun, when it was on the main sequence, burning hydrogen in its core, it’s estimated to have been just under 20 solar masses. If we had seen it during that stage, it would have been one of those bright blue O-type stars like we love to enjoy in the Orion nebula. Orion is a massive star forming region. That entire swath of the sky is rich in all the things needed to make stars, and there’s lost of young stars in that direction.

                                    Well, Betelgeuse isn’t necessarily young; it finished burring all of that hydrogen. But because it’s so massive, as it evolved off of the main sequence, as it expanded out, it didn’t go through this massive flash that we see in smaller stars where it suddenly was like, “Boom, I’m gonna burn helium in my core.” Instead, because it was so massive, it was able to gradually transition into doing this. And as it did, it just basically migrated sideways across the color magnitude diagram, that Hertzsprung Russell diagram, ending up in the top, center of that diagram, being cool, red, and kind of unable to hold onto all of its atmosphere.

Fraser Cain:                 Yeah. And you say that it’s kind of – it’s not young anymore, but compared to the age of our sun –

Pamela Gay:                Oh, yeah.

Fraser Cain:                 – it’s super young. Right? It’s a baby.

Pamela Gay:                Yeah.

Fraser Cain:                 It’s only – or it’s – it’s already old anyway. It has a very short life.

Pamela Gay:                It – it was only on the main sequence for millions of years, unlike the billions of years that our own sun will spend there. About a million years ago, it ran out of that hydrogen. And this is where we start asking, “Okay. So, when did it really settle in to being this nice, glorious supergiant that we see now, this red supergiant?” And the red supergiant is linked to, okay, we have burning going on on the inside, we’ve had a dredge-up of materials, and we think that all of these things have only been going on for tens of thousands of years.

Fraser Cain:                 Wow.

Pamela Gay:                And when you start being able to consider that humanity has been around longer than the given the phase of a star that we’re observing, you recognize how short a period of time this is.

Fraser Cain:                 Yeah. And possibly even, like, agriculture has been around, right?

Pamela Gay:                Yeah.

Fraser Cain:                 Agriculture has been around for longer possibly than Betelgeuse has been in this red giant phase. So, let’s talk a bit – like, what’s going on? Now you mentioned that it is burning. Obviously, it is not burning wood and coal –

Pamela Gay:                Right.

Fraser Cain:                 – in the core, but what is – what is happening to the star right now and causing it to do some of the weird stuff that it does?

Pamela Gay:                So, we can’t know exactly what layers it’s burning at even given moment. These stars like to hide what’s going on in their heart. What we know is while it is this red supergiant, it is going to start out burning helium in its very core with a shell of hydrogen around that. It is then going to transition. As it burns that helium into heavier elements, it’s going to transition into burning carbon, nitrogen, eventually silicon until eventually it ends up with an iron core. And it’s at this point that the star goes kaboom.

Fraser Cain:                 Right.

Pamela Gay:                And during this process, it’s giving off massive amounts of light. What this means is it has a massive light pressure pushing outwards. And that’s what is able to support this star that is bigger in radius than Jupiter’s orbit.

Fraser Cain:                 Crazy.

Pamela Gay:                Doesn’t reach all the way to Saturn.

Fraser Cain:                 Right.

Pamela Gay:                But it’s trying.

Fraser Cain:                 Yeah, but it could gobble – it would gobble up Jupiter.

Pamela Gay:                Oh, yeah.

Fraser Cain:                 Yeah. But it varies. And so, I mean, it is a variable star. And part of the variation comes from literally the change of the star’s size.

Pamela Gay:                Yes.

Fraser Cain:                 So, it’s not always the size that it is right now, and it changes quickly.

Pamela Gay:                And it changes all the way down to, we think, roughly asteroid belt-sized orbit. It’s hard to tell –

Fraser Cain:                 So like tens of millions of kilometers, possibly like a hundred million kilometers across its radius is getting bigger and smaller.

Pamela Gay:                And it’s really hard to nail this down. And one of the reasons it’s so hard to nail this down is how do you define the edge of a cloud?

Fraser Cain:                 Right.

Pamela Gay:                This star at its outermost layer – light pressure is greater than gravitational pull sometimes. And this means it’s pushing its material away. And this outflow is building clouds around it. And this is part of what makes it so hard to figure out the real age and evolutionary stage of the star, actually, because in an ideal situation we’d look at it. And sure, you can’t measure its diameter, you can’t really tell exactly how much mass it has lost, but you can get a pretty darn good estimate by measuring how much mass is around the star.

                                    But Betelgeuse is what we call a runaway star. Due to something bad that happened in its past, it is flying through space at a fairly high velocity, and it’s losing mass as it goes. And because it’s losing mass as it goes, it’s literally leaving its mass behind.

Fraser Cain:                 Right. Like a cometary trail.

Pamela Gay:                And so, we can’t figure out how much mass it’s lost because we don’t know where it left it.

Fraser Cain:                 Right. Right. Because it’s been moving for – for hundreds of thousands, millions of years. Now, let’s pretend like it will die soon. What will happen and what will remain?

Pamela Gay:                Well, we don’t know all the details of what stars do before they go boom. If we did, these radical diming events that we’re gonna talk more about –

Fraser Cain:                 Yes. Yeah. We’ll get to the diming. Don’t worry.

Pamela Gay:                – would be less exciting. What we think is the star will essentially run out of the ability to keep producing energy.

Fraser Cain:                 Like, it just runs out of fuel.

Pamela Gay:                Yeah.

Fraser Cain:                 The fuel that it was using in the core.

Pamela Gay:                And so, all that light pressure that was pushing out, it’s gonna stop being produced. Now, light takes a long time to exit a star. And so, it’s gonna be a gradual coming in on itself. It’s gonna accelerate and accelerate until all a sudden the infalling material, which is heating up as it goes, is going to stop just generating enough pressure to maybe hold the star together a little bit better. And it’s instead going to start hitting the pressures and the accelerating inward, driving more pressure, that is gonna cause a supernova.

                                    Now, this object we suspect, the star we suspect, will be order of 15 solar masses when it goes boom. Order of. Again, we don’t know where it left all its mass. And that means it’s gonna leave behind most likely a neutron star.

Fraser Cain:                 Right.

Pamela Gay:                So, we’re gonna have a classic supernova event, neutron star left behind. Think Crab Nebula, but way closer.

Fraser Cain:                 Right.

Pamela Gay:                In my head, the way I think about this, is some day in the future when they’re teaching about the constellations and the methodology, they can upgrade the story so that Orion has a bloody shoulder from where Taurus gauged him or something.

Fraser Cain:                 Yeah. I mean, imagine a – and it probably would be visible with the unaided eye.

Pamela Gay:                Oh, yeah.

Fraser Cain:                 Like, not the explosion. Like, the explosion would be absolutely visible.

Pamela Gay:                Yes.

Fraser Cain:                 And possibly – and definitely visible in the daytime, and possibly even brighter than the full moon.

Pamela Gay:                Yes.

Fraser Cain:                 I’ve heard estimates. So, it’ll be ridiculous. But even after it’s done and gone, the remnant will probably be bright enough to just see with your eyes just there in the sky.

Pamela Gay:                Yeah.

Fraser Cain:                 It’ll be about the size – I mean, when you think about, say, the Crab Nebula after a thousand years-ish is – is a teeny tiny blotch in a fairly big telescope. Like, I’m imagining something that is like the size of a full moon in the sky that is just this big, red, blasted smear in the sky –

Pamela Gay:                And –

Fraser Cain:                 – where there used to be a star.

Pamela Gay:                The Crab Nebula is more than ten times further away.

Fraser Cain:                 Yeah. Yeah. So, ten times closer, bigger than the Crab Nebula.

Pamela Gay:                That means a hundred times brighter.

Fraser Cain:                 Yes.

Pamela Gay:                And so –

Fraser Cain:                 Thanks to –

Pamela Gay:                – we’re gonna have something that’s a hundred times brighter. Now, it’s always going to be spread out over a larger area on the sky. So, it’s not that every arcsecond is going to be a hundred times brighter, because you have to deal with the fact that the light’s spread over a larger area but there’s more of that light getting to us. And this is a calculation I need to do. I meant to do it in time for the show, but day job got in the way. Stay tuned. This is something I’m probably gonna do for fun –

Fraser Cain:                 Yeah.

Pamela Gay:                – on my blog at some point. But yes, we’re gonna have something bigger in the sky that we’re gonna be able to see by eyeball. It’s just a matter of how long are we gonna be able to see it before it gets so big that its light’s spread out too much.

Fraser Cain:                 Right. And we have examples – we do have examples of that. There’s like the Veil Nebula – the whole Cygnus supernova complex is this gigantic supernova remnant that is a huge portion of the sky. You need to take multiple images in a telescope to be able to see it. And that’s an example of one that exploded a long time ago, and we’re just seeing the wreckage just expand outward into space. So, imagine if it was a lot more compact and a lot closer and a lot brighter. So, yes. Yes, please.

                                    Okay. So, let’s shift now to the sort of the recent excitement, the reason why Betelgeuse has come across everybody’s newsfeed and why everybody is so excited that maybe this time it’ll explode for real. So, why – so, explain the dimming. What’s going on?

Pamela Gay:                Well, we don’t know exactly what’s going on, but I can tell you what we observed.

Fraser Cain:                 Yeah. Tell me what we observed.

Pamela Gay:                So, normally Betelgeuse varies in brightness by a couple of magnitudes, worst case. And this brightening and dimming has a multiyear period density to it and it also has a hundreds-of-days period density to it. So, you have all these complex, just how bright does it get, how faint does it get at any given period, is a combination of both of these semi-regular, sometimes forget that they’re actually supposed to do something variations. This is what’s called a semi regular pulsating star. It – it’s not entire understood why these stars pulsate because really, it’s like a cloud in the parts of the star that’s undergoing these pulsations.

                                    And so, this super diffused material is changing how big the star is, which is changing how much surface area is giving off light, which is changing the luminosity of the star. As it changes in size, it’s also changing in temperature. Fine. We’ve been observing this for hundreds of years, no big deal. But for reasons no one can yet explain but we’re trying to get all the possible observational data to eventually be able to explain it, Betelgeuse dropped down to 35 percent of its normal luminosity. Now, I’m not saying it was 35 percent off. I’m saying it was 35 percent of.

Fraser Cain:                 Of.

Pamela Gay:                Of its normal brightness, 65 percent off.

Fraser Cain:                 Right. That’s a sale.

Pamela Gay:                That is –

Fraser Cain:                 I could buy – I’ll buy two of them.

Pamela Gay:                Yes, please.

Fraser Cain:                 And save one for a rainy day.

Pamela Gay:                So, this means that folks going outside, looking at Betelgeuse who are used to seeing this amazing right – bright red star as one of their way finders in the night – and this includes me here – is going outside and suddenly is like, “Wait, where’s Orion? I can’t find it.” Because that thing you look for suddenly was the same apparent magnitude as the other shoulder.

Fraser Cain:                 Yeah. Yawn.

Pamela Gay:                Yeah.

Fraser Cain:                 Yeah.

Pamela Gay:                It starts masquerading as like the top two heads of Gemini or something, and you need to find the whole constellation before you can make sense of it.

Fraser Cain:                 Yeah. So, before the dimming, it was regularly the 11th brightest star in the sky, and right now it’s the 25th, which is – come on, Betelgeuse, you can do better than this. Right? We expect more from you. Top 25? That’s – that doesn’t even compete now. Okay. So, why do astronomers think that it’s dimming?

Pamela Gay:                Well, we have three competing reasons. The two likely ones are it possibly puffed a blast of dust our direction and that dust is obscuring how we see the star. It’s distorting the shape we see, and essentially scattering light so that we see the entire star as dimmer. What we should be able to see is its brightness, as a function of color, changes in ways that are distinctive of warm dust instead of warm star. It won’t be the black body that we’re used to.

Fraser Cain:                 Right.

Pamela Gay:                So, we’re looking to see that.

Fraser Cain:                 An analogy that I think about is like when you see the moon, like a full moon but there’s part clouds and you can see – and the wind is moving really quickly, you can see these clouds just moving in front of the moon like – and the moon is just changing in brightness and dimness as these clouds are moving past. And so, imagine – but the clouds – but the moon was throwing out its own clouds.

Pamela Gay:                Right.

Fraser Cain:                 And that’s what’s – right. So, there’s one. Just clouds of dust that it threw out recently or a long time ago that happened to be obscuring our perspective, and that will clear up. So, what’s one of the other ideas they’re thinking of?

Pamela Gay:                Well, the other is just like our own sun, Betelgeuse has convective cells. We talked about this last week in our episode. And these convective cells on Betelgeuse are much, much larger. And if you have the cooling flows of two different convective cells interacting in interesting ways, you can potentially end up with a big old cool spot that we’re looking at that is going, “Hi, not generating as much light. Gonna make the whole star look fainter here, people.”

Fraser Cain:                 Yeah.

Pamela Gay:                And so, this could be an atmospheric effect where just changes in the churning of this roiling gas are giving us a cool perspective. Again, this is a thermodynamic –

Fraser Cain:                 Literally.

Pamela Gay:                – effect. Literally.

Fraser Cain:                 Yeah. Literally a cool perspective, yeah. And as you said, right, we talked about that last week with the pictures of the sun, and that you see those convective cells, those bright blobs of gas. And then you see the darker regions around it. And they’re still incredibly, insanely hot. It’s just that they are darker compared to the hot parts. And so, same thing, that you’re getting less light in total just based on the way you’re seeing the star, the perspective you happen to be getting, the right combination of gigantic convective cells and then darker regions.

Pamela Gay:                And just like sunspots on our own sun can be bigger in size than Earth, the sunspots on Betelgeuse, we think the biggest can be bigger than our sun.

Fraser Cain:                 Oh, way bigger. So, I’ve heard they are 60 percent – they can be 60 percent the size of Betelgeuse. So.

Pamela Gay:                That is significantly bigger than our sun.

Fraser Cain:                 Yeah. Yeah. Yeah. So, like the orbit from the – from the sun to Mars – or I guess the – from the sun to Jupiter. Right? So, imagine a sunspot that is hundreds of millions of kilometers across.

Pamela Gay:                Yeah. That’s big.

Fraser Cain:                 Yeah. And again, I doublechecked that, and it’s not 60 percent the size of the sun. It’s 60 percent the size of that sun, Betelgeuse. Okay. So, that’s two reasons. Right? You’ve got dust, you’ve got just like a happenstance of convective cells. And what? The third idea is just that it is in one of these expanding and contracting phases.

Pamela Gay:                And the added step of that is that it’s in one of the contracting phases. And as its surface area gets smaller, the amount of light we get will last. And maybe we just completely screwed up how old the star is. Maybe the star evolved off the main sequence much longer ago than we thought. Maybe we’ve misjudged when it had its first dredge-up and we don’t fully understand the chemistry in the outskirts of a star. And maybe it actually is gonna go boom, but very, very few people – it’s basically the “We’re hoping we’re completely wrong because we wanna see a supernova.”

Fraser Cain:                 Right. Yeah.

Pamela Gay:                Can we please be wrong?

Fraser Cain:                 And so, let’s talk about – I mean, obviously we know that it could explode some point within the next hundred thousand years or so, maybe the next million years or so. We could be the ones to witness it.

Pamela Gay:                Yes.

Fraser Cain:                 But there’s no reason to believe that this is – this is the – this is that time.

Pamela Gay:                No. Betelgeuse doesn’t care what you or I want.

Fraser Cain:                 Right.

Pamela Gay:                It just follows the rules of physics.

Fraser Cain:                 So, why does dimming not tell us that it’s about to turn into a supernova?

Pamela Gay:                Because there’s these other effects that can make it dim as well.

Fraser Cain:                 Right.

Pamela Gay:                And –

Fraser Cain:                 And there was an interesting post from Ethan Siegel. He was sort of talking about this. And the gist is just like it just takes time for things in the core of the star to reach the surface, thousands of years. And so, whatever we’re seeing in the core, whatever is happening in the core, we won’t know about it for thousands of years. And not just like the time it takes for the light to get from – but the time is takes for that radiation to actually make it through the material in the star. So, whatever features you’re seeing on the surface of the star right now, aren’t necessarily what’s happening inside the star.

Pamela Gay:                And this is where looking at its long-term behavior matters so much. It was talked about by Ed Gehring back in December that this is an unusual low, but if it’s just something having to do with its normal periodicity it should start to rebrighten right about now.

Fraser Cain:                 Yep.

Pamela Gay:                And –

Fraser Cain:                 It kind of looks like it has flatlined, right?

Pamela Gay:                It doesn’t just look like it’s flatlined, but for the past two days, multiple observers, observations combined, are showing that it just might be starting to rebrighten.

Fraser Cain:                 Right.

Pamela Gay:                So, instead of being that low of 35 percent its normal brightness, it’s now crept its way up to being 39 percent of its normal brightness.

Fraser Cain:                 Right.

Pamela Gay:                And so, maybe it’s starting to come back out, in which case the question becomes what is the slope? And that starts to tell us what might be causing this effect. We’re catching a star in the process of dying. Human society might actually even last long enough for us to document the entire thing. I mean, who knows.

Fraser Cain:                 Yeah.

Pamela Gay:                Maybe you’ll still be around in 100,000 years in your –

Fraser Cain:                 In my – yeah, in my robot body.

Pamela Gay:                – one cell – yeah, yeah. But this is the first time we’ve gotten to document this.

Fraser Cain:                 Yeah.

Pamela Gay:                This is a star six hundred lightyears away. It’s not that far away in the grand scheme of things. It’s big enough we can see it as multiple pixels on a detector. We can see its sunspots, we can see right now, using the very large telescope and its sphere instrument that the shape has changed. This is not the spherical star we saw a year ago. This is this weird, distorted something that – it may not be physically distorted, but the places where the light is coming out are –

Fraser Cain:                 Yeah, yeah.

Pamela Gay:                – distorted.

Fraser Cain:                 And I think that’s important. Yeah. So, I had – it looked – when you look at the pictures, you can see this sort of really bright blob at the top and this darker region down – it looks like the star is blobbing out, but it’s almost certainly that it’s just a region that is bright and shining and a region that is less shiny.

Pamela Gay:                And –

Fraser Cain:                 Possibly with a cloud, as I mentioned, passing in front of it. Or –

Pamela Gay:                And the way –

Fraser Cain:                 But it’s not actually.

Pamela Gay:                – to think of this is a super dirty lampshade outside. I have some outdoor lampshades that dirt and grime and stuff have all gathered in the bottom of the lightshade. And so, when you look at the light, it’s not this pretty sphere of light; it’s this modeled grossness reminding me I need to clean the lampshades.

Fraser Cain:                 Right.

Pamela Gay:                Well, the dust and grime around Betelgeuse, the darkness from whatever convective cells may be merging, all of these different things can add up to what appears to be a non-spherical star that’s just spherical, but doesn’t have a blob of dead bugs like my lamp.

Fraser Cain:                 Right.

Pamela Gay:                But it’s got a blob of dust.

Fraser Cain:                 Right. So, I think as we bring this episode home, it’s absolutely fascinating star, wonderful that we have such an incredible red, supergiant so close to us. Probably not gonna explode in our lifetime, but –

Pamela Gay:                But I want it to.

Fraser Cain:                 Of course. We all do. Come on. And anyone who’s worried about the Betelgeuseians, they’ve only known suffering for the short – few short millions of years this star has been around.

Pamela Gay:                It’s true.

Fraser Cain:                 That the explosion of this star would be really just icing on the cake of just a few short million years. Like you can just imagine, right? Your star –

Pamela Gay:                Our solar system hadn’t even finished the great heavy bombardment at the point in its history that is the same number of years as the Betelgeuse system has been around. It’s a baby solar system.

Fraser Cain:                 Yeah. Yeah. So, like, think about how long planets take to form. It’s already died in that process. Not to mention, it is pumping out radiation at obnoxiously high levels. Not to mention, it changes in size from –

Pamela Gay:                Bigger than Jupiter’s orbit.

Fraser Cain:                 – from the size of the asteroid belt to the size of Jupiter. You try to live near a star that’s changing – like, there is nothing habitable around Betelgeuse. When that star goes –

Pamela Gay:                We can see it.

Fraser Cain:                 – we’ll be able to see it. Well, but we’ll keep you posted if anything does happen. Pamela, do you have any names for us this week?

Pamela Gay:                I do. I just wanna once again, thank all of you out there who support us month after month. And we’re here thanks to you. Susie is able to do all the heavy lifting around here, and we can pay her because of your patronage. And we couldn’t do this show without having her there to do all the heavy lifting. So, I wanna thank those people who really made this possible.

And this week, I’m gonna thank Michelle Cullen, Neuterdude, William Lauer, Eric Farenger, Ryan James, Shannon Humber, Kristin Brooks, Glenn McDavid, Dan Litman, Kseniya Panfilenko, Dean, Matthias Heyden, Benjamin Davies, Russell Peto, Martin Dawson, Cemanski, Dana Nourie, Bart Flaherty, Father Prax, Andrew Stephenson, Kenneth Ryan, Dean McDaniel, Donald E. Mundis, and Anitusar.

Fraser Cain:                 Awesome. Thank you, everyone, for your continued support of what we do. You support us directly so that you can get your space news from us as opposed to relying on some traditional, old school media channel. I mean, I’m not saying it’s aliens.

Pamela Gay:                It’s not aliens.

Fraser Cain:                 It’s not aliens. All right. Thanks, Pamela. We’ll see you in several weeks. So, stay tuned when the next episode comes out when I’m back from Japan. Thanks, everybody.

Pamela Gay:                Bye-bye.

Female Speaker:          Thank you for listening to Astronomy Cast, a nonprofit resource provided by the Planetary Science Institute, Fraser Cain, and Pamela Pamela Gay. You can find shell notes and transcripts for every episode at Astronomy Cast. You can e-mail us at info@astronomycast.com. Tweet us @astronomycast, like us on Facebook, and watch us on YouTube. We record our show live on YouTube every Friday at 3:00 p.m. Eastern, 12:00 p.m. Pacific, or 1900 UTC. Our intro music was provided by David Joseph Wesley, the outro music is by Travis Sorel, and the show was edited by Susie Murph.

[End of Audio]

Duration: 36 minutes

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1 Comment

  1. Hello.

    I just listened to Ep. 560: Betelgeuse and I have a question. While listening to the podcast I was wondering what similarities or dissimilarities between Betelgeuse and La Superba (Y CVn, Y Canum Venaticorum) and Hind’s Crimson Star (R Leporis)? Will Betelgeuse turn into a carbon star and then go nova? Will La Superba and Hind’s Crimson Star go nova? Am I just a big ball of confusion?

    Love your podcast and I do follow you on twitter.

    Joe Kononchik
    @JoeKononchik

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