Stars are huge balls of burning plasma. But, with the exception of the Sun, they appear as tiny points of light in the night sky.  Moreover, our Sun is not the smallest or largest star. There are many much more massive and big stars than the Sun. Some of them have evolved since their formation. Others grow as they “age.”

To answer the question about which star is the largest in the universe, we “sorted” the stars according to such criteria as size. The equatorial radius of the Sun, which is 696,392 kilometers, was taken as a unit of measurement for the stellar radius.

This celestial body, also known under another name (HR 5171 A), belongs to the yellow hypergiants and is a double star. Its smaller “partner” HR 5171 B orbits V766 Centauri every 1,300 Earth days.

This star is located in the direction of the constellation Cepheus, about 5 thousand light years from Earth. The red hypergiant, with a radius approximately equal to 1050-1900 solar radii, is part of a binary star system. Its companion is the small blue star VV Cephei B, which orbits its “big brother” in an elliptical orbit. The star is named after the larger of the pair, and is now known as one of the largest double stars. Milky Way.

To get a closer look at this red supergiant from the constellation Scorpio, people would have to travel a distance of 7,400 light-years. The radius of Scorpio AH is 1411 times greater than the solar radius.

7. VY Canis Majoris

This star is associated with heated debate among astronomers. According to estimates updated in 2012, its radius exceeds the radius of the Sun by 1420 times. However, according to Robert Humphreys' initial estimate, the radius VY Canis Major 1800 - 2200 times more solar. The exact radius of the stellar giant has not yet been established. When it can be known for sure, the leader in the ranking of the biggest stars may change.

The radius of this hypergiant star is at least 1,420 times the radius of the Sun, and its brightness level is as much as 300,000 times higher than the Sun. It is located in the constellation Cygnus, at a distance of about 5 thousand light years from Earth.

This star belongs to the class of hypergiants - the most powerful and brightest, the heaviest and at the same time the rarest and short-lived supergiants. Its radius is approximately 1520 times greater than the solar radius.

VX Sagittarius is located in the constellation Cepheus, 9000 light years from our planet. It is so huge that it could easily cover the orbital path of Saturn if it were in the place of the Sun. The star's red color indicates that its temperature range is between 3000 and 4000 Kelvin. Hotter stars have a yellow color, while very hot ones take on a bluish tint.

At a distance of 11,500 light-years from our planet, the star cluster Westerland 1 is home to the fourth largest star in the galaxy. Its luminosity is 380 thousand times greater than the Sun, and if placed in the place of our yellow star, its photosphere would absorb the orbit of Jupiter. The photosphere is where the star becomes transparent to light, and where photons—that is, light particles—can disappear. The photosphere allows astronomers to approximate the “edges” of a star.

Here is another star known to science from the constellation Cepheus, included in the list of the largest. The radius of this red supergiant is about 1600 solar radii. If RW Cepheus were in the place of the Sun, the radiating layer of its stellar atmosphere (photosphere) would extend beyond the orbit of Jupiter.

The second largest star in space is located in the constellation Doradus, 160 thousand light years from our world. Despite the fact that this star has lost up to a third of its original mass due to stellar wind, a thick ring layer of gas and dust torus has formed around it for many years. The star's "dimensions" were adjusted to take into account all the mass present in its ring. It is expected to go supernova in a couple of thousand years.

1. UY Scuti (UY Scuti) - the largest star in the universe

At a distance of 9,500 light years from the Sun, in the constellation Scutum, lies the largest star in the world. Her approximate size is almost eight astronomical units, where one astronomical unit is the distance between the Earth and the Sun. This is enough to extend the UY Scuti photosphere into Jupiter's orbit.

UY Scuti is so gigantic and so bright that you can see it with powerful binoculars on a dark night. It is visible along the stars of the Milky Way, and appears as a reddish star with a faint spot.

Study of a supergiant

In the summer of 2012, astronomers, using the Very Large Telescope complex located in the Atacama Desert in Chile, measured the parameters of three red supergiants near the Galactic center. The objects of study were UY Scutum, AH Scorpio and KW Sagittarius.

Scientists have determined that all three stars are 1,000 times larger and more than 100,000 times brighter than the Sun. They also discovered that UY Scuti is the largest, brightest of all three stars. From the radius and luminosity, an effective temperature was obtained - 3665 ± 134 K.

Mass and dimensions of UY Scuti compared to the Sun

The exact mass of this star is unknown, primarily because it has no visible companion star from which its mass can be measured by studying gravitational interference. According to stellar evolutionary models, the star's initial mass (at formation), corresponding to a red supergiant stage such as UY Scuti, would have been around 25M☉ (possibly up to 40M☉ for a non-rotating star) and would have burned continuously. Presumably, its current mass is 7-10 M☉ and continues to decrease. UY Scuti is not only the largest, but also the fastest burning star currently known to science.

UY Scuti's mass is just over 30 times the mass of our Sun, which doesn't even approach the top of the list of most massive stars. This honor belongs to the star R136a1, which has 265 times the mass of the Sun, but only 30 times the radius of the Sun.

Mass and physical dimensions do not always correlate for celestial bodies, especially for giant stars.  So, although UY Scuti is only 30 times more massive than the Sun, it has a radius somewhere in the region of 1700 times our radius daylight. The error in this measurement is about 192 solar radii.

Is life possible near UY Scuti

The habitable zone, or the orbital zone with the highest probability of life, is a complex thing, the possibility of which depends on several factors. The planet on which life originated should not be too far or too close to the star. According to astronomers, the habitable zone around UY Scuti will be from 700 to 1300 astronomical units (AU). This is crazy long distance. The number in kilometers is simply incomprehensible - it is about 149,597,870,700 km. For comparison, the habitable zone in the Solar System is located at a distance of 0.95 to 1.37 AU from the Sun.

If a living planet is at a safe distance, say 923 astronomical units from UY Scuti, a year on it would be 9612 Earth years. That's almost 2500 years of winter! And 2500 years of summer. That is, many generations will change who know only one season.

UY Scuti may indeed have a planetary system in this zone, but if it does, it won't last very long. You, the reader, may reasonably ask: “Why”? Because the star's future is too bright.

What awaits the star in the future?

Based on modern models evolution of stars, scientists suggest that UY Scuti began to merge helium into the shell around the core. As the helium flows out, the star will begin to drain heavier elements such as lithium, carbon, oxygen, neon and silicon. The star's location deep in the Milky Way suggests that it is rich in metal. After the fusion of heavy elements, its core will begin to produce iron, upsetting the balance of gravity and radiation, resulting in a supernova. This will happen in a million years - not very long by astronomical standards, but humanity has time to prepare for such an enchanting spectacle.

After the supernova, UY Scuti will most likely turn into a yellow hypergiant, a blue variable star, or even a Wolf-Rayet star with a very high temperature and luminosity. In the latter case, it will “give birth” to many new stars after its supernova.

Modern astronomy defines stars as huge plasma balls consisting of incandescent mass. Humanity has always been interested in the question of what is the largest star in the Universe and what is its size. This rating includes the TOP 10 largest similar facilities, known to mankind. However, it has a certain degree of convention - there are probably even larger luminaries in space, but we don’t know about them yet, and some of them are variable stars capable of contracting and expanding.

Mu Cephei

One of the largest and most powerful stars in our Galaxy with a luminosity 350 thousand times greater than the Sun is rightfully included in the TOP ten stars of our rating. It is approximately 650-1420 times larger than our star, and from its size it becomes clear which largest star is huge. Mu Cephei can accommodate up to 1 billion Suns and 2.7 quadrillion objects such as Earth in its area. If we imagine our planet in the form of an ordinary golf ball with a diameter of 4.3 cm, the width of this star on this scale would be 5500 meters, which is twice the corresponding size of the Golden Gate Bridge. Mu Cephei is 60 thousand brighter than the Sun, and its bolometric luminosity exceeds the solar luminosity by 350 times. At the same time, it belongs to the category of dying, since scientists have recorded irreversible processes of carbon synthesis on it.

V766 Centauri

The ranking of the largest stars also includes yellow supergiants. The radius of V766 Centauri is 1490 times larger than the Sun. The object has one distinctive feature- in fact, it is a double star along with HR 5171. Its “companion” is much smaller and is so close that it practically touches the more massive star. They are located in the constellation of the same name at a distance of about 12 thousand light years from the Sun.

AN Scorpio

Being a red supergiant with a radius of approximately 1411 solar, the object confirms the assumption of what the largest star looks like and what size it is. It is separated from Earth by 7.4 thousand light years. The star is surrounded by a dusty shell, and sources of its microwave radiation include water and silicon oxide. During the observation period, they approached AN Scorpius at a speed of 13 km/s, which confirmed the ongoing process of compression of the giant.

KY Swan

The hypergiant, thanks to its radius of 1420 solar, rightfully took its place in the TOP 10 largest stars in the Universe. This is a borderline star, and if it had a lower luminosity, it would no longer be classified as a supergiant. Located 5 thousand light years from Earth. KY Cygni is a very bright object that exceeds our star in this indicator by at least 138 thousand times.

VX Sagittarius

Another red supergiant included in the list of the largest. It belongs to the group of semi-regular variable stars; according to scientists, it is gradually losing mass due to the influence of stellar wind. Large stars in the Universe, as a rule, are located at a great distance from Earth and VX Sagittarius is no exception - it is separated from our planet by about 5250 light years. The radius of the giant star ranges from 850 to 1940 solar, and its diameter probably exceeds the similar parameters of the asteroid belt of the Solar System.

Westerland 1-26

A red hypergiant located in the constellation Altar. It was discovered by the Swedish astronomer B. Westerlund in the star cluster system Westerlund 1. Anyone who wonders what the largest star is called needs to know that the luminosity of Westerlund 1-26 exceeds that of the Sun by 380 thousand times, and its surface temperature exceeds 3000 K. In the ESO photograph Westerlund 1 appears to be one of the most massive open clusters in the Galaxy.

RW Cepheus

A red hypergiant whose name comes from the constellation Cepheus. It is located 11.5 thousand light years away from our planet. It is no coincidence that it is included in the TOP 10 largest stars, since its radius is 1535 times greater than the solar radius. The luminosity of this large object is 625 thousand times greater than that of the Sun. At the end of its life, it can become a hypernova, and its core transforms into a black hole.

WON G64

The red supergiant of the Doradus constellation, the second largest star in the Universe. Its estimated radius can reach at least 1540 solar. According to astrophysicists, this large object, one of the TOP largest stars, has lost up to 1/3 of its mass due to stellar wind. Using the Very Large Telescope complex located in Chile, it was possible to obtain an image that helps to understand that the dust and gas around WON G64 forms a torus, reducing its luminosity to 280 thousand solar.

VY Canis Majoris

The hypergiant, well known to astronomers, which is named after the constellation of the same name, reaches a size of 1600 solar radii. Moreover, the mass of the object included in the list of the largest stars is only 17 times greater than the Sun, which confirms its extremely low density. The volume of the giant is 7·10 15 times greater than that of the Earth. Astrophysicists studying the star using the Hubble Space Telescope say it will explode as a hypernova in 100,000 years. This photo of VY Canis Majoris shows the star expelling large volumes of gas during its outburst.

UY Shield

A true supergiant located in the Scutum constellation. According to astronomers, its radius is 1708 solar, and its diameter reaches 2.4 billion km. The largest star in the Galaxy has a volume that exceeds the parameters of the Sun by 5 billion times. The star is defined as a variable red hypergiant with an estimated pulsation period of 740 days. In the visible part of the spectrum, its luminosity exceeds that of the sun by 120 thousand times, in the absence of clusters cosmic dust UY Scuti could be one of the five objects that can be viewed from Earth with the naked eye.

>The largest star in the Universe

UY Scuti is the largest star in the Universe: description and characteristics of the star with photo, location in the constellation, distance from the Earth, list of the largest stars.

It's easy to feel tiny when looking at the night sky. You just need to select an object for comparison. How about a star? Just look into the territory of the Scutum constellation and you will find the largest star in our galaxy and visible universe- UY Shield.

In 1860, the star was found by German scientists at the Bonn Observatory. But only in 2012 it was possible to conduct a survey with the Very Large Telescope (Atacama Desert). Since its discovery, it has become the largest star in size, surpassing Betelgeuse, VY Canis Majoris and NML Cygnus.

Of course, there are record holders for brightness and density, but UY Scuti has the largest overall size, with a radius of 1,054,378,000 - 1,321,450,000 miles, which is 1,700 times the Sun.

People think that the Earth is huge. But let's take an 8-inch ball. Then, in terms of scale, the Sun will be 73 feet in diameter, which is greater than the height of the White House. Now let's put UY Shield next to it and get a diameter of 125,000 feet.

What happens if you put UY Scutum in the solar position? The star will dine on the first five planets and leave the orbital path of Jupiter. But many people think that it is even capable of crossing the orbit of Saturn.

Well, let’s be glad that the star is still not located in the Solar System and is 9500 light years away.

It is important to emphasize that with the improvement of terrestrial instruments, we are discovering new objects that are distant over long distances. This means that one day we may come across an even bigger star.

It is worth noting that the largest known stars are represented here, since many objects remain outside the field of view. Also, some of these are variables, which means they are constantly compressing and expanding. Now you know what the biggest star in space is. Let's look at the rest of the ten biggest stars in the universe:

List of the largest stars in the Universe

The radius of the red supergiant VY Canis Majoris reaches 1800-2100 solar, making it the largest in the galaxy. If placed in place, it would cover the orbital path. Located 3900 light years away in the constellation Canis Major.

It is a red supergiant, 1000 times the radius of the Sun. Located 6000 light years away. Represented by a binary system where the main star is accompanied by a small blue one.

Mu Cephei

Mu Cephei is a red supergiant whose radius is 1,650 times larger than the Sun's and 38,000 times brighter.

V 838 Monoceros is a red variable star located 20,000 light years away. It can reach the size of Mu Cephei or VV Cepheus A, but the large distance makes it difficult to determine accurately. The range covers 380-1970 solar radii.

A red supergiant that is 1540 times larger than the solar radius. Located in the constellation Dorado.

V354 Cephei

A red supergiant, 1520 times the solar radius. Located 9000 light years away in the constellation Cepheus.

KY Swan

1420 times larger than the solar radius, although some estimates put the figure at 2850 times. The star is located 5,000 light years away and has not yet been able to obtain a clear image.

KW Sagittarius

The red supergiant is 1,460 times larger in radius than the Sun. Located 7800 light years away.

RW Cepheus

A red supergiant with a radius of 1600 solar. From the position of the Sun, it could reach the orbital path of Jupiter.

A red supergiant whose radius is 1000 times greater than the Sun. This is the most popular star, as it is located quite close (640 light years) in . It can transform into a supernova at any moment.

My six-year-old daughter is a question-asking machine. A couple of days ago we were driving from school and she asked me about nature. One of her questions was, " Which star is the largest in the Universe??" I gave a simple answer. "The universe is a big place," I said, "and there is no way we can know which star is the biggest"But that's not the real answer.

Radius and mass of the Sun:

When talking about star sizes, it's important to first look at ours for a sense of scale. Our star has a diameter of 1.4 million kilometers. This is such a huge number that it is difficult to get a sense of scale. By the way, the Sun accounts for 99.9% of all matter in our planet. In fact, you could fit a million inside the volume of the Sun.

Using these values, astronomers created the concepts of "solar radius" and "solar mass", which they use to compare stars of larger or smaller size and mass to our Sun. The solar radius is 690,000 km and the solar mass is 2 x 10 30 kg. This is 2 nonillion kilograms, or 2,000,000,000,000,000,000,000,000,000,000 kg.

Illustration of a Morgan-Keenan spectral diagram showing the differences between main sequence stars. Credit: Wikipedia Commons.

It's also worth considering the fact that our Sun is quite small, a G-class main sequence star (specifically a G2V star), which is commonly known as being on the smaller side of the size chart (see above). Although the Sun is definitely larger than the most common M-class stars, or red dwarfs, it is itself a dwarf (no pun intended!) compared to blue giants and other spectral classes of stars.

Classification:

Stars are grouped based on their characteristics, such as spectral type (i.e. color), temperature, size and brightness. The most common classification method is called the Morgan-Keenan (MK) system, which classifies stars based on temperature using the letters O, B, A, F, G, K and M, with O being the hottest stars and M being the coldest. Each letter class is divided into numerical subclasses from 0 (hottest) to 9 (coldest). That is, the hottest stars are O1, and the coldest stars are M9.

In the Morgan-Keenan system, luminosity class is added using Roman numerals. This is done based on the specific width of absorption lines in the star's spectrum, which vary depending on the density of the atmosphere, which distinguishes giant stars from dwarfs. Luminosity has classes 0 and I as applied to hyper- and supergiants; classes II, III and IV as applied to bright, normal giants and subgiants, respectively; class V for main sequence stars; and classes VI and VII apply to subdwarfs and dwarfs.

Hertzsprung-Russell diagram showing the relationship between star color, luminosity, and temperature. Credit: astronomy.starrynight.com

There is also a Hertzsprung-Russell diagram relating to stellar classification by absolute magnitude (i.e. true brightness), luminosity and surface temperature. The same classification is used for spectral types, starting with blue and white on one end to red on the other, which then groups the stars together by absolute magnitude, placing them on a two-dimensional plot (see above).

On average, O-class stars are hotter than other classes of stars, reaching effective temperatures of up to 30,000 Kelvin. At the same time, they are larger and more massive, reaching sizes of more than 6.5 solar radii and up to 16 solar masses. At the lower end of the diagram, K- and M-class stars (orange and red dwarfs) tend to be cooler with temperatures ranging from 2400 to 5700 Kelvin, which is 0.7 - 0.96 from and somewhere between 0.08 - 0. 8 of solar mass.

Based on full classification our Sun (G2V), we can say that it is a main sequence star with a temperature of about 5800 Kelvin. Now let's look at another famous star system in our galaxy - Eta Carinae- a system containing at least two stars located at a distance of 7500 light years from us in the direction of the constellation Carina. The main star of this system is estimated to be 250 times larger than the Sun, has a mass of at least 120 solar masses, and is a million times brighter than the Sun, making it one of the largest and brightest stars ever observed.

Eta Carinae, one of the most massive known stars, is located in the constellation Carina. Credit: NASA

There is currently debate about the size of this star. Most stars emit a stellar wind (the same as wind), losing mass over time. But Eta Carina so large that it sheds 500 times more mass annually. With such mass loss, it is difficult for astronomers to accurately measure where the star ends and the stellar wind begins. In addition, scientists believe that Eta Carina will explode in the not so distant future, and it will be the most spectacular thing people have ever seen.

In terms of sheer mass, first place goes to star R136a1, located at a distance of 163,000 light years from us. It is believed that this star may contain 315 solar masses, which is a mystery to astronomers as they believe that stars can only contain a maximum of 150 solar masses. The answer lies in the fact that star R136a1 was most likely formed when several massive stars merged together. Needless to say, R136a1 could explode like .

In terms of big stars, a good (and popular) example is Betelgeuse. Located in the shoulder of Orion, this famous supergiant has a radius of approximately 950-1200 solar radii, at which radius the Sun would be absorbed in our Solar System. In fact, whenever we want to put the size of our Sun into perspective, we often use Betelgeuse to do this (see below).

However, even after we use this lumbering red giant to compare the Sun to larger stars, there are still larger stars left. Let's consider star WOH G64, a red supergiant located in the Large Magellanic Cloud, approximately 168,000 light-years from Earth. With a diameter of 1540 solar radii, this star is currently the largest star known to us in the Universe.

But there is also RW Cepheus, an orange hypergiant in the constellation Cepheus, located 3500 light years from Earth and measuring 1535 solar radii in diameter. Star Westerland 1-26 (Westerlund 1-26) unusually large, it is a red supergiant (or hypergiant), located in the stellar supercluster Westerlund 1 at a distance of 11,500 light years from us and measuring 1,530 solar radii in diameter. Meanwhile, stars V354 Cephei and VX Sagittarius also have huge dimensions of 1520 solar radii in diameter.

The largest star is UY Scuti (UY Scuti)

The title of the biggest star in the Universe(that we know of) comes down to two contenders. For example, UY Shield Currently at the top of the list, located 9,500 light-years away in the constellation Scutum, this bright red supergiant and pulsating variable star has an average radius of 1,708 solar radii - or 2.4 billion kilometers (15.9 AU) , thereby giving it a volume of 5 million volumes of the Sun.

However, this average estimate includes an error of ±192 solar radii, which means the radius of this star could be either 1900 or 1516 solar radii. The lower bound places it on par with V354 Cephei and VX Sagittarius. Meanwhile, the second largest star in the list of possible biggest stars- This NML Cygni (NML Cygni), a semi-regular variable red hypergiant star located in the constellation Cygnus at a distance of 5300 light years from Earth.

An enlarged image of the red giant UY Scuti. Credit: Rutherford Observatory/Haktarfone.

Due to the location of this star in , it is heavily obscured by dust. As a result, according to astronomers, its size can range from 1642 to 2775 solar radii, which means it could become the largest star known in the Universe(with a margin of about 1000 solar radii), or in fact the second largest, keeping up with UY Shield.

Just a few years ago the title most big stars wore VY Canis Majoris(VY Canis Majoris), a red hypergiant in the constellation Canis Major, located 5000 light years from Earth. Back in 2006, Professor Roberta Humphrey of the University of Minnesota calculated the upper limit of its size to be 1540 times larger than the Sun. Its average mass, however, was 1420 solar masses, which places it in 8th place behind V354 Cepheus and VX Sagittarius.

The above were listed biggest stars, which we know about, but most likely there are dozens of larger stars hidden by dust and gas, so we don’t see them. But even if we can't detect these stars, we can speculate about their likely size and mass. So how big can stars be?? Once again, Professor Roberta Humphrey from Minnesota gave the answer.

Comparison of the sizes of the Sun and VY Canis Majoris, a star that once held the title largest known star in the universe. Credit: Wikipedia Commons/Oona Räisänen.

As she explained in her article, largest stars in the universe- the coldest. Therefore, although Eta Carina is the brightest star we know of, it is extremely hot (25,000 Kelvin) and therefore only 250 solar radii in diameter. The largest stars, on the contrary, will be cold supergiants. As in the case VY Canis Majoris, which has a temperature of 3500 Kelvin, and a really large star will be even cooler.

At 3000 Kelvin, Humphrey estimates the cool supergiant would be 2600 times the size of the Sun. This is below the upper limit of estimates for NML Swan, but above the average ratings for both NML Swan, and for UY Shield. Therefore, this is the upper limit of the star (at least theoretically and based on all the information we have to date).

But as we continue to peer at the Universe with all our telescopes and study it with robotic spacecraft and manned missions, you are sure to find new amazing things that will continue to amaze us!

And be sure to check out this amazing animation below, which shows the sizes of various objects in space, from tiny to star UY Scuti. Enjoy!

Title of the article you read "Which star is the largest in the Universe?".