View Full Version : Ep. 75: Stellar Populations

2008-Feb-11, 09:10 PM
After the big bang, all we had was hydrogen, a little bit of helium, and a few other trace elements. Today, we’ve a whole periodic table of elements to enjoy, from oxygen we breathe to the aluminium cans we drink from to the uranium that powers some people’s homes. How did we get from plain old hydrogen to our current diversity? It came from stars, in fact successive generations of stars.http://feeds.feedburner.com/~r/astronomycast/~4/233353716

More... (http://feeds.feedburner.com/~r/astronomycast/~3/233353716/)

2008-Feb-13, 09:24 PM
re the early universe - as the first generation stars reached the end of their lives, would I see a sky filled with multiple supernova events?
What sort of frequencies would be expected, i.e. 1 per year, 10 per year?

2008-Feb-16, 06:28 PM
Great show, thanks!
Together with that older show about the types and life cycles of stars,
it really makes for an excellent overview.

One question about the metallicity:
does anybody have actual numbers (%) on how much metal each star generation typically contains/contained?
If I got that right, it's still a very low percentage, even in population 1 stars...

Wikipedia (http://en.wikipedia.org/wiki/Abundance_of_the_chemical_elements#Abundance_of_el ements_in_the_Universe) says all elements other than hydrogen and helium
only make up about 2% of visible matter in the Universe,
but I suppose that's the cumulative matter ALL star generations have produced so far,
so the metallicity of most stars should be lower, correct?

2008-Feb-24, 10:15 PM
Hi 4tune8: It is generally thought that the massive stars outnumbered five solar mass and less the first billion years following the big bang, so galaxies our size might have a supernova every year or two. The spacing between the galaxtic groups was also smaller, so we could see supernova in other galaxiy groups, brighter, except there was likely more obsuring dust. Neil

2008-Feb-27, 12:32 AM
In case anybody is interested, I've started a new thread (http://www.bautforum.com/questions-answers/70821-metallicity-stars.html) about this on Q&A, and got some good answers and links...