Science > Physics > For Those with Subscription to Science Magazine: First Stars in theUniverse
| Topic: |
Science > Physics |
| User: |
"Sam Wormley" |
| Date: |
01 Aug 2005 01:39:11 PM |
| Object: |
For Those with Subscription to Science Magazine: First Stars in theUniverse |
First Stars in the Universe
The first stars in the universe are believed to have formed shortly
after the Big Bang and are likely to have been massive yet short-lived.
Models of early star formation posit that the first stars formed from a
primordial hydrogen-helium gas cloud and contained no metals (carbon
and heavier elements like iron). Their demise is believed to have
spawned a second generation of stars that recorded the elemental
compositions of their progenitors. The recent discovery of "hyper metal
poor" stars led to hopes that the earliest generation of stars, the
so-called Population III, had been found.
Now, a report in the 15 Jul 2005 Science (published online 2 Jun 2005)
by Iwamoto et al. (http://www.sciencemag.org/cgi/content/short/309/5733/451 )
suggests otherwise. The researchers described computer modeling of the
elemental abundance of the two most iron-poor stars known today. The
detailed abundance patters indicates that these stars are actually
second-generation objects that formed from the supernovae of an earlier
population of stars.
Their results also suggest that stellar masses in the early universe
may have included first-generation stars with only 25 times the mass of
the Sun and that these lower-mass stars are responsible for the
elemental abundance patters now observed in the second-generation
stars. An accompanying Perspective by T. C. Beers (
http://www.sciencemag.org/cgi/content/short/309/5733/390 ) highlighted
the report.
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