Lead
In the solar system, the huge size and mass of the sun belong to the word "big", but the absolute position of the sun in the solar system cannot be ignored, because its mass and volume account for almost 99.86% of the total mass of the solar system.
Despite this, there are still many huge stars in the Milky Way, and these stars often have a volume and mass that are many times larger than the Sun.
UY Scuti, the largest star in the solar system, is 1,700 times the size of the Sun, and Stevenson 2-18 is even more unimaginable, as it is 10 billion times the size of the Sun.
So, how did these two huge stars form?
一、盾牌座UY Scuti。
UY Scuti is a red supergiant located in the constellation Shield, about 9,500 light-years away from Earth, and its diameter is also very large, about 1,700 times that of the Sun, that is, its volume is about 5 billion times that of the Sun.
The star is also a very rare star, as it is one of the most massive stars in the Milky Way and one of the largest known stars.
Scientists have made different estimates of the mass of UY Scuti in the constellation Shield, but most of them are between 7 and 30 solar masses, so it is difficult for scientists to judge its evolutionary path, because the mass of this star is at a critical value.
In addition, its luminosity is also very amazing, about 340,000 times the luminosity of the sun, put it in the solar system, its surface temperature is about 3000K, and its luminosity is very amazing, then it looks bright.
But its actual luminosity is not very high, only 1/3 of the sun, which is also due to its low surface temperature, therefore, its luminosity is not very high.
UY Scuti is also very old, about 50 million years old, and there is no burning material left in its core, so it will no longer ignite new starlight.
And, because of its very large mass, in the future, it may explode into a supernova or form a black hole, indicating that its life has come to an end.
2. Stephenson 2 Star Cluster.
Stevenson 2-18 is located in the Stephenson 2 cluster, its diameter is very large, about 2158 solar radius, and its size is terrifying, its volume is equivalent to 100 billion times that of the sun, therefore, its size is far larger than that of UY Scuti in the constellation Shield.
And its mass is about 40 times the mass of the sun, and its volume is 100 billion times that of the sun, so its density is very low, even though it is a huge star, but its density is very low.
Stevenson 2-18 is also one of the largest stars in the Milky Way, but because it is not very massive, it is not very luminous, about 440,000 times the luminosity of the sun, and its surface temperature is about 3200 K.
Stevenson 2-18 is 20,000 light-years away from Earth, its age is about 25 million years, and the reason why it is so large is because it has a large amount of substances such as helium and hydrogen in its core, and the main components of these materials are nuclear fusion.
Its surface temperature is very low, so its color is very deep, which is why the brightness of Stevenson 2-18 is low.
However, its size is very large, so its mass is extremely large, about 40 times the mass of the sun, but in the universe, a star with 40 times the mass of the sun is not considered a heavyweight star, but its volume is much larger than that of a heavyweight star.
Stevenson 2-18 is not the largest star in the Milky Way, but it is the largest star in the Stephenson 2 cluster.
Stevenson 2-18 is too large, therefore, it is also very massive, about 40 times the mass of the sun, and its peripheral material is not very stable, so its mass may fluctuate somewhat.
The Stevenson 2-18 eruption could have an impact on the stars around it, and as a result, scientists have also characterized it as an unstable star.
Stevenson 2-18 is very massive, but its outer material is not very stable, and once it runs out of outer material, then it will die, and its death may explode in the form of a supernova, or form a black hole.
3. The brightness of Stevenson 2-18.
Stevenson 2-18 is about 440,000 times the luminosity of the sun, its surface temperature is about 3,200 K, and if it is placed in the solar system, it is only 440,000 times brighter than the sun, which is the so-called "bright star" in the night sky.
Stevenson 2-18 is not very hot on the surface, so its color is darker, and Stevenson 2-18 is only a faint star in the Milky Way, so its brightness is not very high.
However, due to the sheer size of Stevenson 2-18, it is very luminous at about 440,000 times that of the Sun, making it one of the largest stars in the Milky Way.
Stevenson 2-18 is very large, so it also has a lot of hydrogen and helium in its core, and the fuel in its core can be burned for millions of years, but its age is only 25 million years, so its age is very small.
It is also very large, which also gives it a huge radiation pressure, so its luminosity is also very high, about 440,000 times the luminosity of the sun, and it also has a huge gravitational pull, but the gravitational pull of Stevenson 2-18 does not make it contract, because it is a nuclear fusion reaction going on in its core.
There is an equilibrium between nuclear fusion and radiation pressure, which is why Stevenson 2-18 is not getting smaller, but is still expanding.
But the fate of Stevenson 2-18 in the future is likely to form a super-large black hole, because although its mass is large, the mass of Stevenson 2-18 is not very large.
After the death of Stevenson 2-18, a supermassive black hole may form, or a planet similar to Saturn in the solar system may form, and the outer material of Stevenson 2-18 will drift through the solar system.
epilogue
The volume and mass of Stevenson 2-18 are estimated by scientists, and there are different scales for estimating the mass and volume of stars, and scientists need to use advanced technology and models to understand the characteristics of stars more accurately.
The volume and mass of stars also need to be estimated with the help of advanced technology and models, and with the continuous progress of science and technology, human beings may discover larger and more exotic stars, which will also expand human understanding of the universe.