The Corona Supernova - Sixty Symbols

professor I didn't think I'd be talking to you again so soon after we saw your backyard astronomy but we've got breaking news in space you've been imaging it what's going on up there yeah it's not often that we get things happening you know as slot presses we have for this particular event but there's been supernova has gone off in Messier 61 so one of our Messier objects has put you on a show at the moment I know there are different types of supernova what's this particular one so this is a type 2 supernova which means that when you split the light of it up into a spectrum you find there are absorption lines of hydrogen in the spectrum so what this is telling you is that whatever is exploding you're seeing through a lot of hydrogen so the hydrogen is kind of obscuring a bit of the explosion and absorbing some of the light and that tells you that what you're looking at is a massive star which still has all its sort of outer layers of hydrogen on it so there's an explosion going on in the core of this star that we're seeing through the outer layers of hydrogen of the star itself so it still had lots of fuel in the tank sort of it has fuel and some of it will still be actually physically bound to the star some of it will have blown out into space in the late stages of its lifetime but yes most doors end up with a lot of their hydrogen left over before they blow up okay so can you talk me through what a type 2 supernova actually is what happened to this ill-fated star sitting there in m61 so this is a star right at the end of its life it's a lot more massive than the Sun it's at least 8 times the mass of the Sun and it's gone through all the nuclear fuel burning stages it's only hydrogen into helium into carbon into all the heavier elements it's run out of fuel and the the nuclear fusion is really what holds the star up you know the pull of gravity is trying to pull it in was on itself and the the nuclear reactions in the center us of generating the energy necessary to hold it up against gravity when you run out of those reactions the whole thing just collapses down and ends up imploding essentially the whole star collapses down onto the the center of where the star used to be you end up forming a neutron star right at the center as everything gets very compressed the store then sort of bounces off that neutron star flings its outer layers out turns out that's not quite the whole story that's not enough to make the star explode but the other thing that happens is the neutron star in the center is initially incredibly hot and starts cooling down and part of the way it cools down is by producing pairs of neutrinos which then also fly out through the star some of those interact with the gas that's just been flung out and end up creating the enormous explosion that we see the location that has happened within the galaxies of interest to is and it seems to be in one of the the arms of the galaxy is that normal yeah I mean so it's a very massive star massive stars have very short lifetimes at least by stellar standards we're talking about you know hundreds of thousands to millions of years which really means that they don't move very far from where they were born before they blow up and most stars form in spiral arms so because it hasn't had time to move out of its sort of birthplace you actually see it blowing up within the spiral arm where it was born so most stars are born in spiral arms because that's where all the gas and the energy and all the all the stuffs kicking off but they don't stay there it's not like as the arms swirl around the galaxies the stars go with them no you should think of spiral arms as like waves which are traveling around the galaxies and they travel around the galaxies at their speed and the Stars travel around the galaxies at their speed and they're not the same in most parts of the galaxy in fact for most of the galaxies the stars and the guests that make up the galaxies travel faster than the spiral arms and so the way that stars form is that a gas cloud will travel traveling faster than the spiral arm will sort of catch up with it and overtake it but as it passes through the spiral arm it gets compressed by the density wave with the spiral arm and that compression is what triggers the star formation and then the after the stars are formed the star as massive as this supernova hadn't had time to travel very far it sort of started traveling towards the front edge of the spiral arm but it won't have got very far and so you'll still see it in the spiral arm when it blows up okay so it's almost like all the gas is being lit up by the arms as the arms move around and stars form when they light up and then but the stars will move at the speed that the gas was moving at not the speed that the waves were moving at yes so the stars will continue if it was a slightly less massive star that wasn't destined to explode shortly after forming it would have continued and continue moving away from the front edge of the spiral arm as it travels faster than it okay so the Sun for example moves in and out of spiral arms as it merrily goes around the Milky Way which it's done a few times already yeah the Sun as you know it takes about what a couple of hundred million years travel around the Milky Way and it's been around for billions of years so it had gone round the Milky Way tens of times since it was born but this poor one in m61 it didn't get far it hardly got off the ground no it really wasn't this you know it's as soon as it was born basically it blew up at least in sort of stellar terms and so actually it really didn't have very much time to travel anywhere it's the Sun currently in or out of a spiral arm I think we're in between at the moment it's not not in a particularly exciting by the Milky Way at the moment will we be able to go back into the archive of pictures of m61 and find the star that blew like say that was the one that's where it was that was the one that was just about to go and learn anything from that I don't know in this particular case but it is something that people are doing more and more often now with Hubble Space Telescope image quality you can actually see the very bright stars that go supernova has individual stars before they blew up so if there happens to be a picture of the right part of m61 then it will be possible to go back and in fact this is one of the ways we learn about the supernova process is by looking at these progenitors these stars which you're gonna blow and learning what kind of star it is that is just before it blows up how it looks just before it explodes will we be able to go back afterwards when all the light dies down and find the remnants see what's left behind probably not in this case because it's almost certainly too faint I mean for supernova 1987a in the Large Magellanic Cloud so very much closer there with really good imaging from the Hubble Space Telescope we've been able to start studying the remnant that formed behind the explosion but this is just so much further away I very much doubt we'll be able to see anything once the supernova itself has faded away now because this has happened during the pandemic locked out I was all excited because this was you know I was going to call this the corona supernova but you've sent me straight a bit and apparently these are not particularly rare events these things are banging all the time they really are and because so this one was discovered with a telescope called the zookie transient facility which is actually out scanning the skies the entire time it covers the entire northern sky every few nights so it's collecting huge amounts of data and will find pretty much all the super novae that go off sort of within its range and so that actually when it used to be the case we'd find you know maybe a dozen or so supernovae a year but now with all these automated searches out there we're finding literally thousands of supernovae and we've actually had to change the way we named super novae a bit to make this fit in that for example supernova 1987a it was called that because it was found in 1987 it was the first one in 1987 and we used to just work our way through the alphabet and then it turned out that actually you run out letter to the alphabet so then we went into using two letters so once you've used all the single letters then you'd have a a a b a c and so on but it turns out now we're finding so many super novae that even two letters aren't enough so now now we have to go through three sets of the alphabet and so this for example was super nova 2020 gif oh and i'm sure the next few supernovae have already been found since then so actually we sort of is that the meat is clocking up very quickly on the names of supernovae now is that possible or is it ever happened that someone is looking at a galaxy and the supernova goes off like you see the moment it blinks into existence you'd have to be very lucky but actually there are an awful lot of astronomers out there staring at the skies so sooner or later you'd think it probably will happen yeah that'd be awesome you should be out there doing that just what m60 ones a good candidate you're telling me that's bit of a hotbed for supernovas yeah it is because although so typically you expect in a galaxy you know like the Milky Way or m61 you expect maybe one supernova every 50 years but actually this one has had you know it had one Sarris had one this year there was another one in 2014 there at least another couple since 2000 so this one is a real real supernova Factory at the moment no one I think really understands why why one galaxy would suddenly produce a whole bunch of super novae I think it really just given the very short timescale involved it has to be just down to chance but yeah if you were well it depends which way you look at it right maybe you say well m60 one's had its fair share now so you want to go and look somewhere else but more maybe you want to say well you know m60 ones on a roll so maybe we should just keep looking there if a supernova went off in a spiral arm and you were in the same spiral arm that would be pretty that a big good site wouldn't know it would be pretty impressive so you remember a little while ago there was a lot of excitement about maybe beetlejuice was going to go and there you'd have had a supernova that you'd have been able to see during daytime from the earth which is about you know relatively nearby star to us so yeah indeed if you were in the right spiral arm in m61 you'd be getting a bit of a show at the moment yeah but you'd be safe as long as that wasn't your star you want to be a reasonable distance away because there are gamma rays and nasty things but but as soon as you get you know unless it really is a nearby neighbor you're probably fine are you gonna keep imaging this and watch it brighten up and fade away or have you you've got a bit bored with this one now and you're moving on no I'm gonna strike so this one was caught really early I think it's still brightening up so it'd be interesting to map out its light curve to see how its light changes over the coming weeks although I think I'm gonna be slightly at the mercy of the weather in that the forecast looks cloudy for at least the next week you were pretty lucky to get this one there waiting you were showing me you had to like thread the needle between the trees and the house and that that's where it is at the sky and things yeah there's a tiny little patch of sky I could aim at so it was m61 is kind of in the south from here and so the south is the direction of my house from the back garden which means that actually unless it's quite high in the south you end up looking at my house rather than the object but it turns out there's a tiny little patch of my garden where you can just set up the telescope and see it and sort of next to the chimney pot and I got lucky and actually really lucky in that the clouds cleared just the right moment for me actually you'd be able to capture an image of it you'll be able to get like an occultation with the chimney pot well I have actually had things disappear and thought I wonder where that's gone and it's because the task goats tracked in such a way that the house is going the way alright oh you think you found this amazing supernova it's your office window or something yeah no you will you you've got to be careful when you start pointing your telescope into bedroom windows though spiral structure is that when you calculate the precession speed of all these orbits you find that they're all the same that's how spiral structure gets generated it's in the case where you can have all those ellipses processing at the same speed and that precession so if you can think about it you can think about the Stars going around and then the ellipse itself is rotating I've said I've solved the squeak by the way you know what I solved the squeak that's good well done wd-40 no I just cranked the seat of the chair back so I can't lean back

Channel: Sixty Symbols

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Id: u65EA7J15VI

Length: 11min 3sec (663 seconds)

Published: Mon May 11 2020