Why Do Some Stars Grow So Massive?

[mjacobsca]

Why are some stars so much more massive than others? Eta Carinae and The Pistol Star are 100X more massive than the Sun. When stars are forming, doesn't hydrogen fusion begin at about the same mass and density for all stars? Or does chemical composition and rotational velocity of the nebular gas cloud contribute to such huge variations? I assume Eta Carinae had a larger amount of available gas in the first place. But if fusion can start when the star has accumulated smaller mass like our Sun, why doesn't it ignite and push the remaining gas away before growing larger? Can it accumulate more mass from the gas cloud after igniting? I also assume collisions with other stars are rare enough not to be considered.

 

[turbo]

I suggest that you Google "stellar accretion rates" and start browsing the papers and following the citations in them.

 

[Lost in Space]

Why are some stars so much more massive than others? Eta Carinae and The Pistol Star are 100X more massive than the Sun. When stars are forming, doesn't hydrogen fusion begin at about the same mass and density for all stars? Or does chemical composition and rotational velocity of the nebular gas cloud contribute to such huge variations? I assume Eta Carinae had a larger amount of available gas in the first place. But if fusion can start when the star has accumulated smaller mass like our Sun, why doesn't it ignite and push the remaining gas away before growing larger? Can it accumulate more mass from the gas cloud after igniting? I also assume collisions with other stars are rare enough not to be considered.

From what I understand, red giants are really long lived stars and much less dense and cooler than the short-lived massive hot stars that produce the higher elements in nuclear fusion and distribute them by becoming supernovae.

 

[Misericorde]

The honest answer is that some stars (not 100x) such as hypergiants, much like supermassive black holes, don't have one clear explanation. Stellar formation isn't exactly a mystery, but it's an ongoing realm of study with unanswered questions.

 

[pmacias]

There are several factors that can contribute to why some stars are much more massive than others. One factor is the amount of available gas in the nebular cloud from which the star forms. As you mentioned, Eta Carinae likely had a larger amount of gas to begin with, allowing it to accumulate more mass and grow larger.

Another factor is the chemical composition of the gas cloud. Stars that form from gas with a higher concentration of heavy elements, such as carbon and oxygen, may be more massive because these elements can help to increase the density and temperature of the gas, making it easier for fusion to occur.

The rotational velocity of the gas cloud can also play a role in the size and mass of a star. If the cloud is rotating rapidly, it can help to prevent the gas from collapsing and forming a larger, more massive star.

In terms of hydrogen fusion, it is true that it typically begins at about the same mass and density for all stars. However, the rate of fusion can vary depending on the star's mass. For example, a more massive star will have a higher rate of fusion and will therefore consume its fuel faster, leading to a shorter lifespan.

It is also possible for a star to continue to accumulate mass after fusion has started. This can happen through processes such as accretion, where the star pulls in material from its surrounding environment.

Overall, the mass and size of a star are determined by a combination of factors including the amount and composition of gas available, the rotational velocity of the gas cloud, and the rate of fusion. While collisions with other stars may not be a major factor, they can still play a role in the formation of massive stars through processes such as mergers.