Which is the Massive Star Ever Known?

R136a1 is the most massive star yet known and is located in the Large Magellanic Cloud. It is a Hawking behemoth whose mass is about 150-200 times that of our star (Sun).

Understanding the upper limit of stars helps astronomers piece together everything from the life cycles of stars to the history of galaxies.

A team of astronomers studied the R136 star cluster in depth. This star cluster is located at a distance of about 150,000 light years from Earth.
This star cluster is quite large and contains many newborn stars, which makes it appear that it is also a star forming region in Magellanic Cloud.

Based on the picture, astronomers were able to estimate the masses of some stars, including R136a1. It is estimated that their mass is between 150-200 times the mass of the Sun. 
This latest estimate is much less than the previous estimate of this star. However, R136a1 has a surface temperature of about eight times that of the Sun while the radius is forty times larger.

It is likely that R136a1 represents one of the most massive stars in the universe. Stars form in a variety of sizes, from red dwarfs that are one-tenth the mass of the Sun to giants that put our home star to shame.

Understanding how common supergiant stars are helps astronomers to understand their formation. After all, to make such a massive star you need a lot of gas to collapse in a very short time.  

And since on such a large scale they don't last long, they are more difficult to detect.

Galaxies change their lives continuously from generation to generation. The ability to form massive stars depends on the existence of previous generations.

This is because when stars die they release their associated heavy elements into the interstellar medium. Those heavy elements help other clouds of gas to cool quickly and form massive stars without splitting into many smaller ones.

The more we learn about massive stars like R136a1, the more we learn about the history of galaxies.