Metallicity and Stellar Formation

[Drakkith]

What does metallicity have to do with stellar formation? Why does low metallicity in stars in the very early universe mean that they needed to be more massive than modern stars to form?

 

[Chronos]

Metallicity plays an important role in collisional heating and cooling during the protostar phase. Primordial gas clouds were virtually metal and dust free [until contaminated by early SNIe's] which promotes formation of extremely massive stars. For a more thorough discussion see: The First Stars - http://arxiv.org/abs/astro-ph/0311019

 

[zhermes]

Thats an excellent article that Chronos linked.
Another note, however: its only partially that pop III stars had to be more massive; its also that they could be more massive, as radiation pressure is less efficient without metal lines---and thus the Eddington limit is weaker.

 

[Drakkith]

Awesome! Thanks Chronos!

 

[pmacias]

Metallicity refers to the abundance of elements heavier than hydrogen and helium in a star. These elements, also known as metals in astronomy, are crucial for the formation of planets and the development of life. The level of metallicity in a star can greatly impact its properties, including its size, temperature, and lifespan.

In terms of stellar formation, metallicity plays a significant role in the process. The earliest stars in the universe, known as Population III stars, formed from primordial gas that contained only hydrogen and helium. These stars had very low metallicity, as they were formed before the creation of heavier elements in the cores of previous generations of stars.

Low metallicity in these early stars meant that there were fewer atoms to absorb and radiate energy, resulting in less efficient cooling. This made it more difficult for the gas clouds to collapse and form stars. As a result, these stars needed to be more massive than modern stars in order to reach the necessary temperatures and pressures to ignite nuclear fusion and become stable.

On the other hand, modern stars have higher metallicity due to the incorporation of heavier elements from previous generations of stars. This allows for more efficient cooling and formation of smaller, less massive stars.

In summary, metallicity is closely linked to stellar formation as it affects the properties and processes of star formation. Low metallicity in the very early universe meant that stars needed to be more massive to form, while higher metallicity in modern stars allows for the formation of smaller, more stable stars. Further research on metallicity and its impact on stellar formation can provide valuable insights into the evolution of our universe.