Population III Stars Metallicity

Drakkith

Early Population III stars in the universe were very metal poor if not metal free and were apparently required to be much larger than todays stars, up to hundreds of solar masses, to form. What does the metallicity have to do with this?

mfb

Metals can catalyze fusion, metals can emit light and reduce the pressure in gas clouds.
Put everything in a simulation, and you might get some estimate for stellar masses somehow - no idea how this works in detail.

Matterwave

Are you sure this is a causation rather than a correlation? Perhaps older stars were larger for some other reason? I can't see how metallicity would have THIS much of a drastic effect on stellar masses, I would suspect there has to be some other cause along with the metallicity.

Drakkith

I have no idea Matterwave. I've merely read that the reason super massive stars were the only ones that could form was because of metallicity. Or at least that was what I got from it.

nicksauce

I think you can summarize the idea simply: No metals = Less cooling = Higher temperatures = Higher Jeans mass = Higher stellar mass

This seems to be a good overview of the situation (pdf): http://arxiv.org/pdf/astro-ph/0102503v3.pdf

Drakkith

Nice paper, thanks Nick!