Quote:
Originally Posted by Brian W
Yes it was of interest Trevor as yours was also Ron. Digital Universe does a good job of showing how the O.C. and G.C. do occupy different parts of our galaxy. I am hoping that it is also correct to think of G.C.as populated with first (or perhaps 'early') generation stars, hence the low metalicity while O.C. are later generation stars hence the greater metalicity?
Brian
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Greetings John,
Just a piece of trivia regarding the classification of various populations of stars that may be of interest.
At face value many things in science seem counter intuitive. One would think that the earliest stars would be Population I stars, however that is not how they have been classified.
The metal rich stars of open clusters that formed in the spiral arms from material of previous generations of stars are classified as Population I.
The metal poor stars that formed from primordial material at the very early stages of galaxy formation are classified as Population II stars.
And the very first stars which formed from only hydrogen & helium are classified as Population III stars. These stars, being the first stars, would have only spectral lines of hydrogen & helium
No Population III stars have yet been detected. At that early time, the Universe was much smaller and the density of star forming material would have been very high, consequently Pop III stars were likely to have been high mass stars and hence lived very short lives. That said I have heard professional astronomers say that they expect The James Web Space Telescope, which has been optimized to look at IR wavelengths, to detect Pop II stars.
Regards
Trevor