Friday, December 16, 2011

Hubble Captures the Violent Birth of a Star

We know from stellar nurseries we've seen elsewhere that the current model is largely correct. We know from spectrometry that the gas cloud is abundant in light elements and poor in elements that form in later-generation stars, and know also from spectrometry that the star itself is also very rich in light elements. Spectrometry, the the level of light given off, plus the estimated distance also tells us where in the sequence the star is, because the sequence is now very well known. We can further verify a few details -- the solar winds push gas away from the sun, but there are no solar winds before there's a sun to emit them. By measuring output and the degree of push, you can determine how long the gas cloud has been blasted at by the star. If this matches expectation, all's well. If the gas cloud shows evidence of more displacement than can be accounted for, there'd be problems. So far, all looks good.

So although the exact details of stellar formation do shift from time to time, major changes aren't likely. Minor ones, on the other hand, are commonplace. For example, some stellar nurseries close to the galactic centre are being hammered by solar winds from supermassive stars in the region. Current models cannot account entirely for how the stars were able to condense at all under such conditions. (You wouldn't expect fog patches to form in gale force 9 winds for the same reason. If you see fog in such conditions, then there's some extremely freaky condition to explain it - a total lack of air currents or turbulence is possible if you've exactly the right environment, and therefore something similar must exist in these freak star formations. It's an addition to, though, rather than a replacement of existing models.)

Source: http://rss.slashdot.org/~r/Slashdot/slashdotScience/~3/oayN0PUWCRc/hubble-captures-the-violent-birth-of-a-star

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