Life on our entire planet depends on the Sun, and sometimes we do not realize that in fact in the Universe there are many other galaxies and star systems inside them. And our omnipotent Sun is just a small star among billions of other luminaries. Our article will tell you what is the name of the largest star in the world, which can still be captured by the human mind. Possibly, beyond its borders, in still unexplored worlds, there are even more gigantic stars of immense size ...
Measure Stars in the Suns
Before we talk about the name of the largest star, we’ll clarify that the size of stars is usually measured in solar radii, its size is 696,392 kilometers. Many of the stars in our galaxy are in many ways superior in size to the sun. Most of them belong to the class of red supergiants - large massive stars with a densified hot core and a rarefied shell. Their temperature is noticeably lower than the temperature of blue and white stars - 8000-30 000 K (according to the Kelvin scale) and 2000-5000 K, respectively. Red stars are called cold, although in fact their temperature is slightly less than the maximum in the core of our Earth (6000 K).
Most celestial objects do not have constant parameters (including size), but rather are in constant change. Such stars are called variables - their sizes change regularly. This can happen for a variety of reasons. Some variable stars are actually a system of several bodies exchanging masses, others pulsate due to internal physical processes, contracting and increasing again.
What is the name of the largest star in the universe?
At a distance of 9.5 thousand light years from the Sun, there is the constellation Shield. It appeared on star maps at the end of the 17th century, thanks to the Polish astronomer Jan Hevelius. Two hundred years later, German astronomers from the Bonn Observatory added the UY Shield star (U-Igrek) to the catalog. And already in our time, in 2012, it was established that it is UY Shield that is the largest of the known stars within the studied Universe.
The radius of the UY Shield is about 1700 times greater than the radius of the Sun. This red hypergiant is a variable star, which means its sizes can reach even larger values. During periods of maximum expansion, the radius of the UY Shield is 1900 radii of the Sun. The volume of this star can be compared with a sphere whose radius would be the distance from the center of the solar system to Jupiter.
Space Giants: what are the names of the biggest stars
In the neighboring galaxy, the Big Magellanic Cloud, there is the second largest star within the studied space. Its name cannot be called particularly memorable - WOH G64, but you can take note that it is located in the constellation Golden Fish, constantly visible in the southern hemisphere. In size, it is slightly smaller than the UY Shield - about 1,500 radii of the Sun. But it has an interesting shape - the accumulation of a rarefied shell around the core forms into a spherical shape, but rather resembles a donut or bagel. Scientifically, this form is called a torus.
According to another version, the name of the largest star after the UY Shield is called VY of the Great Dog. It is believed that its radius is 1420 solar. But the surface of VY Canis Majoris is too rarefied - the Earth’s atmosphere exceeds its density by several thousand times. Due to difficulties in determining what is actually the surface of a star and what is already its accompanying shell, scientists still can not come to a final conclusion regarding the size of VY Canis Major.
The heaviest stars
If we consider not the radius, but the mass of the celestial body, then the largest star is called as a set of letters and numbers in encryption - R136a1. It is also located in the Large Magellanic Cloud, but it belongs to the type of blue stars. Its mass corresponds to 315 solar masses. For comparison, the mass of the UY Shield is only 7-10 solar masses.
Another massive formation is called This Kiel - a binary giant star in the constellation Kiel. In the 19th century, as a result of an outbreak around this system, a nebula formed, named because of its strange shape, the Homunculus. The mass of Eta Kiel is 150-250 solar masses.
The biggest stars in the night sky
Giant stars hiding in the depths of space are inaccessible to the eye of a simple layman - most often they can be seen only through a telescope. At night, in the starry sky, the brightest and closest objects to Earth will appear to us as large - be it stars or planets.
What is the name of the largest star in the sky and at the same time the brightest? This is Sirius, which is one of the stars closest to Earth. In fact, in size and mass it does not particularly exceed the Sun - only one and a half to two times. But its brightness is indeed much greater - 22 times more than that of the Sun.
Another bright and seemingly large object in the night sky is actually not a star, but a planet. We are talking about Venus, whose brightness is in many ways superior to other stars. Its brilliance is visible closer to sunrise or some time after sunset.