NSF: A Star Is Born ... But How?

[bystander]

A Star Is Born ... But How?
National Science Foundation (PR 10-111) - 01 July 2010

Created in the first three minutes after the Big Bang, hydrogen and helium gave rise to all other elements in the universe. Stars made this possible. Through nuclear fusion, stars generated elements such as carbon, oxygen, magnesium and all the other raw materials necessary for making planets and ultimately life. But how did the first stars come to be? It all hinges on hydrogen atoms coming together to form hydrogen molecules. New research from Columbia University sheds light on this process.

View a webcast with Daniel Wolf Savin of Columbia University.

Researchers Shed Light on Birth of the First Stars
Columbia University - 01 July 2010

In the beginning, there were hydrogen and helium. Created in the first three minutes after the Big Bang, these elements gave rise to all other elements in the universe. The factories that made this possible were stars. Through nuclear fusion, stars generated elements such as carbon, oxygen, magnesium, silicon and the other raw materials necessary for making planets and ultimately life.

But how did the first stars come to be? New research from Columbia University shows that it all boils down to this simple reaction:

• H^- + H → H₂ + electron

First Stars Formed Fast
Science NOW - 01 July 2010

A few hundred million years after the big bang, the universe was dark. Oceans of hot hydrogen atoms and negative hydrogen ions pervaded space. The cosmos as we know it started to take shape when atoms and ions paired up to form molecular hydrogen, which expelled heat out of the gas clouds, allowing them to cool down enough to form the first stars.

But how long did it take molecular hydrogen to form? That chapter of cosmic history has been unclear. Now, by recreating the chemistry of those early gas clouds in the lab, researchers have determined the rate at which hydrogen atoms and negative hydrogen ions combined in the primordial soup. The result gives astrophysicists a firmer handle on the mass of the first stars, reducing the uncertainty in the estimated mass down from a factor of 20 to two, the scientists report in Science.

To Cool or Not to Cool

• Science 02 July 2010, Vol. 329, No. 5987,
  Perspectives, doi: 10.1126/science.1192014

Experimental Results for H₂ Formation from H^– and H and Implications for First Star Formation

• Science 02 July 2010, Vol. 329, No. 5987,
  Reports, doi: 10.1126/science.1187191

[Ann]

I am not allowed to read the articles you linked to. I wanted to read what the articles said about the mass of the first stars. Yes, I saw that the uncertainty had been reduced from a factor of twenty to a factor of two, but what does that say about the actual mass of the very first stars? Could they be a thousand times as massive as the Sun? Five hundred times as massive? Two hundred times as massive? A hundred and fifty times as massive?

Do any of the articles say anything about that?

Ann

[swainy]

Hi ann.

This was in one of the links above.:


"It turns out that molecular hydrogen forms faster than previously thought," Savin says. "That means the first stars likely formed faster than previously expected." Knowing the rate at which the reaction proceeds is an improvement, but it's not enough to nail down the mass of the first stars. "Because we don't fully know the initial conditions from which the first stars formed," he says, "we don't yet reliably know the distribution of masses."

tc

[Ann]

Thanks, Swainy.

Ann

[bystander]

I am not allowed to read the articles you linked to.

You can't link to the National Science Foundation or Columbia University? Why? How very strange.

[rstevenson]

I am not allowed to read the articles you linked to.

You can't link to the National Science Foundation or Columbia University? Why? How very strange.

To quote the web site I get to using either of those article links... "Subscribe/Join AAAS or Buy Access to This Article to View Full Text." So it's not really that we're not allowed, just that it costs.

Rob

[bystander]

I didn't quote from either of the papers in the Science journal. They were, however, mentioned in the articles I did quote. For completeness, I provided the citations. I usually do that. If I can find a free preview, I usually provide it, also.

I apologize if my providing the citations to the relevant scientific journals has caused any confusion, but the journals are not my source. I don't have access to most journals, either. If you couldn't access any of the three news articles I did reference, I would wonder.

I just try to provide links to scientific news stories I find interesting.