Among all the observed celestial bodies , it is quite difficult to establish which is the largest star in our galaxy. This is associated with huge distances in space and the complexity of observations with subsequent analysis of the data. To date, scientists have managed to detect and register about 50 billion luminaries. A more advanced technique allows you to explore the distant corners of space and to obtain new information about objects.
Evaluation and search for supergiants in space
Modern astrophysics in the process of space exploration is constantly faced with a large number of questions. The reason for this is the gigantic size of the visible Universe, about fourteen billion light years. Sometimes, observing a star, it is quite difficult to estimate the distance to it. Therefore, before embarking on a journey in search of a definition of which is the largest star in our galaxy, it is necessary to understand the level of difficulty in observing space objects.
Previously, until the beginning of the twentieth century, it was believed that our galaxy is one. Visible other galaxies were attributed to nebulae. But Edwin Hubble dealt a crushing blow to the ideas of the scientific world. He claimed that there are a large number of galaxies, and ours is not the largest.
Space is incredibly huge
The distances to the nearest galaxies are huge. Reach hundreds of millions of years. For astrophysicists, it’s quite problematic to determine which is the largest star in our galaxy.
Therefore, it is even more difficult to talk about other galaxies with trillions of stars, at a distance of one hundred or more million light-years. In the process of research, new objects are discovered. Discovered stars are compared and determined to be the most unique and largest.
Supergiant in the constellation Shield
The name of the largest star in our galaxy is UY Shield, a red supergiant. This is a variable star, the size of which varies from 1700 to 2000 diameters of the Sun.
Our brain is not able to imagine such quantities. Therefore, for a complete picture of what sizes the largest star in the galaxy, it is necessary to compare with the values that are understandable to us. For comparison, our solar system is suitable. The size of the star is so large that if it is placed in the place of our Sun, then the border of the super giant will be in the orbit of Saturn.
And our planet and Mars will be inside the star. The distance to this "monster" of space is about 9600 light years.
The largest star in the Milky Way galaxy - UY Shield - can only conditionally be considered the "king". The reasons are obvious. One of them is huge cosmic distances and cosmic dust, making it difficult to obtain accurate data. Another problem is directly related to the physical properties of supergiants. With a diameter of 1700 times larger than our celestial luminary, the largest star in our galaxy is massive only 7-10 times from it. It turns out that the density of the supergiant is millions of times less than the air surrounding us. Its density is comparable to the Earth’s atmosphere at an altitude of about one hundred kilometers above sea level. Therefore, it is quite problematic to determine exactly where the boundaries of the star end and its “wind” begins.
At the moment, the largest star in our galaxy is at the end of its development cycle. It expanded (the same process will happen to our Sun at the end of evolution) and began to actively burn helium and a number of other elements heavier than hydrogen. After several million years, the largest star in the galaxy - UY Shield - will turn into a yellow supergiant. And later on - into a bright blue variable, and possibly into a Wolf star - Rayet.
Along with the “king” - the super giant UY Shield - we can note about ten stars with similar sizes. These include VY Canis Majorus, Cepheus A, NML Swan, WOH G64 VV and several others.
It is known that all the largest stars are short-lived and very unstable. Such stars can exist for millions of years or several millennia, ending their life cycle in the form of a supernova or black hole.
The biggest star in the galaxy: the search continues
Observing serious changes over the past twenty years, it is worth suggesting that over time our understanding of the possible parameters of supergiants will differ from previously known. And it is quite possible that in the coming years another supergiant will be opened, with a larger mass or size. And new discoveries will prompt scientists to revise previously accepted dogmas and definitions.