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UY Scuti, Largest Known Star in the Universe

UY Scuti is a red star that can be located in the constellation of Scutum. The star can not be seen by the naked eye, you need a telescope to see it.

UY Scuti is one of the largest giant stars in the milky way and possibly the universe. It is not as some might think, in our Solar System, it is the centre of its own Solar System. In fact, UY Scuti is located close to the supermassive Black Hole Sagittarius A*, the centre of our galaxy a.k.a. Galactic Centre. However as we are unable to measure all the stars, we will not know if that is the case that it is the largest in Universe. To put it in context, if the centre of UY Scuti was where our Sun was, the star's radius would extend out to Jupiter or even as far as Saturn. Other super large stars that could compete for the title of the largest in the galaxy include NML Cygni and VY Canis Majoris. UY Scuti is marginally in the grand sphere of things bigger than NML Cygni and both if placed in our solar system, would stretch out further than the orbit of Jupiter. To put it another way, it is 1.708 times the Sun's radius with a variance of about +/i 192.ref:Aanda.

UY is a semi-regular variable star in that it expands and contracts on an irregular base. The star roughly pulsates about every 740 days. The figure given for its radius is the mean size. ref:wiki Due to its size, it is not going to live as long as Alpha Centauri which the later is a smaller star but burns through its energy at a slower pace. It is currently fusing main helium, of what is left of its hydrogen reserves are small contained in its core. It will one day go supernova or more appropriately to say hypernova.

If you're struggling to put UY Scuti's size into context, try this. If the Earth was 20cm, the Sun would be 22 meters across and UY Scuti would be 40 km. To give you another idea of how big it is, it would take a plane travelling at the speed of light, 14.5 seconds to travel round the Sun, it would take seven hours for the same object to travel round UY Scuti. ref:wiki.fr

You might think that because the star is a massive star, its temperature would match its size. The actual truth is far from that, UY Scuti's temperature is about 3,000 kelvin based on the Hertzsprung-Russell diagram. Size does not normally equate to temperature, its the colour that dictates the temperature. The more blue, the less red it is, the hotter the temperature is.

The location is an estimated location for the star but it gives you an idea where in the constellation's boundary that the star can be located. Even though the star is very large, it is faint in the night sky and you will not be able to see it unaided without the help of a pair of binoculars or telescope. It was only discovered in 1860 by German astronomers at Bonn University during a night survey. Although, there is a star within the circle, I'm not saying it is UY SCUTI.

It will go supernova one day but even though it is a large star, it will not go supernova in the next million years because it has to work through the elements in its core until it gets to Iron. After Iron, it will not be able to continue to fuse elements any further. It is expected to heat up and become a yellow hypergiant star and also most likely shrink as it is become a hypergiant. When it goes Supernova, we'll be too far away for it to have any direct effect on our planet and whatever life is on the planet will be unaffected. Long before UY Scuti goes supernova, Betelgeuse will have gone supernova and its a smaller star. UY Scuti will either become a Neutron Star or a black hole. It is not a Black Hole now, just a very very large star nearing the end of its life.

UY Scuti might well be tiny compared to the largest star in the universe but as there are so many stars not just in this galaxy but others means we don't know and will never know if UY Scuti is the largest in the Universe. The largest star could be in the Andromeda Galaxy for example or even in IC1101, the currently recognised largest galaxy so far discovered in the galaxy, we just don't know.

Extrasolar Planets in Orbit

There is at yet no Extrasolar Planet (Exoplanet) discovered in orbit round the planet although possible, is probably most unlikely. A planet would be tiny compared to the star and detecting a planet from a wobble would be an immense challenge. When a planet orbits a star, it causes the planet to wobble but a planet would have to be extremely large for it to cause the star to wobble. Another method to detect planets would be if a planet transitted in front of the planet. Again, a planet would have to be large to be seen transitting the planet. At present, its regarded as planetless.

Location of UY Scuti

The location of the star in the galaxy is determined by the Right Ascension (R.A.) and Declination (Dec.), these are equivalent to the Longitude and Latitude on the Earth. The Right Ascension is how far expressed in time (hh:mm:ss) the star is along the celestial equator. If the R.A. is positive then its eastwards. The Declination is how far north or south the star is compared to the celestial equator and is expressed in degrees. For UY Scuti, the location is 18h 27m 36.5334 and -12 d 27` 58.866 .

UY Scuti Luminosity

Luminosity is the amount of energy that a star pumps out and its relative to the amount that our star, the Sun gives out. The figure of 56000.0000000 that I have given is based on the Spectral Types page that I have found on the Internet. You might find a different figure, one that may have been calculated rather than generalised that I have done. The figure is always the amount times the luminosity of the Sun. It is an imprecise figure because of a number of factors including but not limited to whether the star is a variable star and distance.

Physical Properties (Colour, Radius) of UY Scuti

UY Scuti has a spectral type of M4Ia-Iab. This means the star is a red star. UY Scuti lies at a distance of 9,500.00 light years away from our Sun and our planet Earth or to put it another way, 2,912.65 parsecs away from the Sun.

UY Scuti has been calculated as 1,708.00 times bigger than the Sun.The Sun's radius is 695,800km, therefore the star's radius is an estimated 1,188,426,400.00.km.

UY Scuti Apparent and Absolute Magnitudes

UY Scuti has an apparent magnitude of 11.20 which is how bright we see the star from Earth. Apparent Magnitude is also known as Visual Magnitude. Magnitude, whether it be apparent/visual or absolute magnitude is measured by a number, the smaller the number, the brighter the Star is. Our own Sun is the brightest star and therefore has the lowest of all magnitudes, -26.74. A faint star will have a high number.

Distance to UY Scuti

UY Scuti is an estimated 9,500.00 light years from our Solar System (Earth and Sun). It would take a spaceship 9,500.00 years travelling at the speed of light to get there. We don't have a space ship that can travel that distance or at that speed yet.

UY Scuti Facts

Alternative Names

Traditional/Proper NameUY Scuti

Visual Facts

Star Type star
Visual / Apparent Magnitude11.20
Naked Eye VisibleRequires a 4.5 - 6 Inch Telescope - Magnitudes
Right Ascension (R.A.)18h 27m 36.5334
Declination (Dec.)-12 d 27` 58.866
Distance from the Sun / Earth9,500.00 Light Years
Spectral TypeM4Ia-Iab
Colour(M) Red

Estimated Facts

Radius (x the Sun)1,708.00
Luminosity (x the Sun)56,000.0000000

Related Stars

Location of UY Scuti in Scutum

UY Scuti Location in Scutum

The map was generated using Night Vision, an awesome free application by Brian Simpson.

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ParimalTuesday, 5th April 2016 5:03:44 PM
Thanks it helped and I would appreciate if you try to put more pics of it and how to locate it in night sky plz it would be super helpful