UY Scuti - The Largest Star Ever Discovered? [OOTW]

there are hundreds of six still ian's of stars in the universe and while the Milky Way contains an estimated 400 billion of those stars that still a comparatively miniscule sample size this incomprehensible expanse means we will never know for sure just how big the biggest star in the universe really is the overwhelming majority of stars are simply too far away for us to ever be able to measure that being said we've discovered no shortage of giants within our own backyard stars that dwarf our Sun as some that could even swallow up most of our own solar system increasingly accurate estimations of size and distance mean that the league table for the list of the largest stars is ever-changing but if we look for the largest star discovered today we come to the Magnificent uy scuti discovered in the 1800's but reclassified as the largest star at the start of this decade uy scuti has some absolutely insane numbers associated with it and today we are going to be taking a look at this Titans profile history possibilities for exoplanets and how the Beast may reach the end of his life pretty soon [Music] uy scuti is a red hyper giant pulsating variable star located roughly 5000 100 light-years from the earth in the constellation of Scouten the star sits in a similar area of the sky to Sagittarius a the engine black hole at the centre of the Milky Way in a fairly central galactic location at just over 7 astronomical units in diameter this gives the star a radius of a massive 1,700 times that of our Sun however despite this massive disparity in size we predict its mass to be between only 7 to 10 times that of our Sun and is nowhere near the record for the most massive star ever discovered this is because star size and star mass don't correlate in a linear fashion but then again we don't have a lot in the neighboring regions to compare it to so it is quite difficult to estimate the stars maths speaking of neighboring regions us scooty is believed to be extremely luminous as you might expect given the size 400,000 times brighter than the Sun perhaps however is not visible to the naked eye and does not appear that bright in the night sky due to the Stars position within the Cygnus rift an area within the Milky Way that is obstructed by its dark bands of dust and gas furthermore uy scuti is also close to the zone of avoidance an area of the night sky we can't really observe because the Milky Way's bright Galactic plane obstructs it from our perspective given this luminosity you would expect uy scuti to be one of the hottest stars out there but that isn't the case either in fact quite the opposite its surface temperature is estimated to be just under 3000 Kelvin in comparison the sun's surface temperature is almost double this at 5778 Kelvin just as it doesn't correlate a mass size does not always correlate to temperature this is because stars that are this enormous in size are almost always no longer in their main sequence the main part of the star's life when the hydrogen fuel the star was created with is being fused in the core when this hydrogen in the core runs out heavier elements such as helium are fused but hydrogen continues being fused on the outer layers of the core when this occurs the outward pressure of the radiation generated is much greater than the immense pressure of the Stars own gravity which causes the star to expand and ballooned to hundreds of times larger than it was during the main sequence this is how you ice QT and the vast majority of other red giants of red supergiant's came to be so large but it also means that it is in the dying stage of its life given that the star is out of its main sequence you'd expect it to be at least a few billion years old but this post-production phase doesn't actually provide us with much insight as to how old the star is it could be billions of years old but because it's so large and ejecting a lot of its mass this instability could be indicative that the star is merely a few million years old and it's just an inefficient style with a short lifespan while this instability doesn't tell us how long it's been around for what it does tell us is that it hasn't got long left to live on a cosmological timescale anyway as we mentioned earlier this star is the largest known star in the galaxy it's radius is approximately 1,700 times larger than the Suns so how do we put this in some kind of perspective well for starters this impressive volume means that you could fit our Sun into the star 5.1 billion times photons traveling at the speed of light would take about 14 and a half seconds to circle the circumference of our Sun but for uy scuti it would take light the best part of seven hours that is seven hours traveling at the fastest speed in the universe were you to fly something around it at a more human speed say if you flew a standard Boeing 777 aeroplane around the surface at its normal operating speed it would take well over 1,200 years to circle it just once you may have already heard this stat but where you to place us QT at the center of our solar system it's seven astronomical unit excess diameter would engulf everything as far out as the orbit of Saturn that's five planets 82 moons and the asteroid belt all consumed by this one star well we can't estimate you ice cuties mass very accurately we know it appears to be ejecting a lot of its mass following the advent of the dying stage of its life is losing mass at a rate of about 5.8 times 10 to the negative 5 solar masses per year so that's zero zero zero zero zero five eight of a solar mass this seems insignificant but in tonnes our solar mass is two with 27 zeros after it so while this amount is not catastrophic when spread out over the entire surface it is still ejecting millions of trillions of tons of solar radiation every year and much more than the average star this gives it a considerable extrasolar surrounding of dust and gas and is yet another indication that this beast is going to go supernova in the not-too-distant future for a star so far away and obscured by so many variable factors we actually know quite a lot about us QT our fascination with the enormous has led us to tirelessly adapt and refine our techniques of star observation and cataloging but it hasn't always been this way so the question is how did the Stars profile begin us scooty was first noted over a hundred and fifty years ago when German astronomers at the Bonn observatory recorded it in a survey in 1960 as you may be aware most stars are named after the survey or catalog they are recorded through such as Messier objects Kepler objects the Henry Draper catalog and the list goes on uy scuti was no exception it was noted during the bonod Derk mustering stellar catalog survey and was declared the 5050 fifth star between twelve and thirteen degrees south as it was originally coined be d12 five oh five five but in the years that followed the brightness appeared to have changed when it was surveyed again leading to the discovery that the star was actually a variable star more specifically a pulsating variable star pulsating variable cells come in many different forms but generally they are a type of star that changes their luminosity and relative size due to the expansion and contraction of layers on the surface of the star variable stars are invaluable to astrophysicists it's through them that we learn a lot more about the interior processes of a star main sequence stars such as our Sun tend to be more stable with outward pressure and inward pressure from gravity counteracted in a relatively stable equilibrium but variable stars pulsate and vary based on the rate of radiation escaping from the core and outer shell layers of the star as there is an international protocol for recording variable stars BD 12 five zero five five was reclassified and became the 38 variable star in the constellation of scooter it was then renamed uy scuti accordingly the title we know it by today the rate that uy scuti pulses is considered irregular but it seems to have a pulsation period of about seven hundred and forty days roughly a little over two calendar years on earth because there is so much obscuring the star we didn't actually know about its enormous size until fairly recently it wasn't until 2012 when us cutie sized was reading to be about 1700 solar radii placing it firmly above the former largest known star canis Duras while we're almost certain that UI scooty is the largest star we've ever discovered it is far from definitive obstruction from light within the Milky Way is just one of the difficulties we face when taking measurements us cuties distance from earth is a contributing factor because of its surrounding area we can't get wholly accurate data on how far away it is and it becomes difficult to then deduce its size as mentioned the former largest star was V Y Canis Majoris and was a fairly well known star among the scientific community while estimates of its size have also had well-defined margins of error we have managed to refine the estimates down considerably in recent years initial estimates when it was first discovered put the star over 3,000 times larger than the diameter of the Sun but this has since been very examined and the boundary now sits between 1420 solar ad to 2000 solar ad which is still quite a wide margin the 2000 solar radius tomato mystic and so it's likely the Canis Majoris is much nearer than 1500 solar radii arc in comparison us qts radius is estimated to be approximately 1780 solar ad give or take 192 this means that even at is lower bound estimate is still in excess of 1500 times the size of the Sun and most likely the larger of the two red hyper Giants there are a few other stars that sit in the league table between Canis Majoris and you are scooty but the estimates of their size are considered much less reliable when comparing stars we always rank based on the lower bound Esther so for example Canis Majoris is classified as 1420 solar radii which probably doesn't do it justice a star larger than that perhaps is wo h g6 for a star within the Large Magellanic Cloud a satellite galaxy at the edge of the Milky Way its parameters are uncertain and sits between 1500 times the size of the Sun and 2500 times respectively which would make it the largest star ever discovered unfortunately is surrounded by a thick envelope of dust and is much further away than most as we analyze so until technology proves this boundary doesn't look set to narrow anytime soon something slightly closer to home is Westerlund 1 to 6 a star with very strong radio emissions but again it has very vague estimates of its size associated with it with a difference in upper and lower bound of over 1,000 solar ad something maybe only a fraction larger than Canis Majoris is HD 1 4 3 183 a veg supergiant with much more precise estimations perhaps just under 1500 solo ad a very similar size to the former largest known star and then finally there are 2 stars from our SGC 1 a young star cluster within the Milky Way which are estimated to be also just under 1500 solar ad but uy scuti of course still takes the grand-prize as the largest known star for now at least but one thing to consider is if it is the largest what implications does that have for its chances of supporting life like most starts us CET may have a planetary system orbiting it but in this case we will likely never be able to observe it due to its low apparent visual magnitude and its sheer size we detect planetary systems orbiting stars by detecting small depth and brightness which can be indicative of a planet passing in front of the star and blocking a small fraction of the light the problem with uy scuti is that it is so enormous that even if a planet did pass in front of it it would be far too small and insignificant to be detectable these small variations in magnitude would be completely distorted by the posting of fluctuations in brightness of the star to where the more matter is constantly being ejected out of the star at a somewhat substantial rate given its size and the massive amounts of stellar radiation this would equate to the possibility of uy scuti having its own planetary system is statistically unlikely but if it were to sustain a human-like civilization there how far away were the planet need to orbit it to be in its habitation zone well we see a one astronomical unit away from the Sun approximately 150 million kilometres for uy scuti the habitation zone is more likely to be about 1.5 trillion kilometres away about 1,000 astronomical units meaning light and heat reaching the planet would take around a month to travel the distance this also means that in order to complete a full calendar year on the planet you would need about ten thousand years to orbit the star just once this means that the planets seasons as we know them at least would last 2,500 years each entire civilizations would likely exist never knowing any other season that the one they were born out of we're talking such vast amounts of time that any intelligent civilizations probably wouldn't even see them as seasons but rather natural climate change if the star ever supported life at any point no matter what form it took the odds suggest that this would have been at some point during the main sequence now this star is far too volatile and ejects far too much radiation to give life a realistic chance of evolving and there's also something else us QT is only expected to burn for another 1 million years its ejection of mass is a sign that is reached the end of its life stars outside of the main-sequence burn for a fraction of the time they would have during the main stage because they are ejecting their outer layers and becoming less stable all of the hydrogen fuel in the core uy scuti was formed with has been used up and the star is now fusing heavier elements turning them into oxygen and carbon however this process will continue and eventually the helium will be all fused up and the process will reach a physically unsustainable point it is thought that us scooty could evolve into another stage before he goes to supernova either into a yellow hypergiant or a much more luminous blue hypergiant or to what is known as a wolf rayet star whatever it evolves into all three eventualities will create strong stellar winds that will expose the core and will mark the beginning of the end based on its location within the Milky Way galaxy we know you were scooty to be a metal-rich star and so eventually the core will begin to fuse iron when it does this no heavier elements can be produced and the outward radiation which once caused it to expand to this incredible size will no longer be strong enough to counterbalance its own gravity causing the Stars outer layers to collapse in an extreme supernova except because of its size this won't just be a supernova it will be a more appropriately named hypernova it will explode with the power of over a hundred supernova explosions emitting high amounts of gamma radiation which will decimate any planetary system around it thankfully earth will be much too far away to be affected and this still isn't likely to happen for at least another million years but then again 1 million years is a pretty short time span on a cosmological timescale following this tremendous explosion if you eye scooty had evolved into a wolf rayet star beforehand then the gas is dispersed by the supernova could act as incubators for new stars following its death like a phoenix rising from the ashes the amount of mass lost in the hypernova will determine what becomes of the leftover dead core if what remains intact exceeds four times the mass of the Sun then it will likely collapse in on itself to form a black hole but if not it will form a neutron star u.s. QT is not particularly massive as we mentioned earlier so if it loses the to share of its mass it will probably not be massive enough to become a terrifying black hole you would typically expect from such a huge star uy scuti is a giant of creation but only within the abridged sample size of the Milky Way galaxy that we have to observe with two trillion galaxies out there and trillions will be on the boundary of the observable universe it seems bit presumptuous to assume that us cootie is the biggest star in the universe as some refer to it as but here's an exciting thought say humanity does manage to colonize the Milky Way galaxy if we can survive approximately 3 and 1/2 billion years into the future then we will probably be around to witness the collision of the Milky Way and Andromeda when this happens our nearest neighbor is due to bring almost 1 trillion new stars with it to bolster our galactic family with this new compound galaxy containing nearly 3 times the amount of stars we have currently imagine what other record-breaking stars we are likely to find but that's a long way off in the future and there are plenty of scientific barriers to cross before then in the mean time thank you very much for watching and don't forget to keep reaching for the stars [Music] [Music] you

Channel: SEA

Views: 2,471,272

Rating: 4.8583002 out of 5

Keywords: Sea 1997, Conspiracy Cases, Sea1997, Sea, 1997, Space, OOTW, Out of this world, astronomy, science, uy scuti, vy canis majoris, woh g64, westerlund 1-26, BD 12 5055, biggest star in the universe, largest star, main sequence, milky way, galaxy, scutum, cygnus rift, hypergiant, supergiant, solar radii, pulsating variable star, HD 143183, RSGC1, Large Magellanic Cloud, habitable zone, supernova, hypernova, wolf-rayet star, milkdromeda, milky way andromeda collision, documentary, space

Id: mPtqmyUGPzw

Length: 17min 59sec (1079 seconds)

Published: Thu Jul 18 2019

Reddit Comments

[u/Randomusername919192]

Well that's gonna make a massive ass blackhole/neutron star

[u/BoJvck34Empire]

It looks like how I imagined Mercury as a kid... Just you know, a quintillion times bigger haha

[u/Turbopowerd]

I dont have patience to watch this long - in short: whats size?

[u/vivzkestrel]

If the earth were the size of a tennis ball, this video clearly shows how big UY Scuti is