Quote:
Originally Posted by Adelastro1
I agree with Renormalised's view. Our sun is a second generation star, ie. has gone through a supernova explosion and re-formed, which makes it a fairly old star (much greater than 5 billion years, which is the age of the erath). The higher atomic number elements above iron (Fe) were formed in that explosion (normal fusion reactions in stars can only produce elements up to Fe, but supernovae produce much higher pressures to fuse elements together to give heavier elements). The Sag stars appear to be younger stars if they are all of similar composition and no elements above about He. If they are of similar size to our sun then they must be younger as they haven't burnt all their Hydrogen/helium yet.
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You're under a couple of misconceptions there. Yes, the Sun is a "2nd generation" star (probably more likely 20th generation, but I know what you mean), but it and the Earth are roughly the same age. We formed along with the Sun from the same cloud of gas and dust 4.657Ga ago. It formed a few million years quicker than we did, but close enough in time to be the same. The supernova you mentioned was probably the one (or one of a number of) that initiated the collapse of the cloud that eventually formed the Sun and the solar system. The Sun and the solar system most likely formed along with a couple of hundred other stars in an open cluster somewhere in the galaxy. Most of those stars have drifted apart from one another due to gravitational effects caused by other stars and the rest of the galaxy...which is the fate of all open clusters, to a greater or lesser extent (depending on where they are).
Most of the stars still left in and escaped from the Sagittarius Dwarf are all older than the Sun. They formed in gases that didn't have as much metal content as the gas we formed out of (due to its age and paucity of star formation). Because a star has less metals doesn't make it younger...some can be (depending on where they form), but less metals usually means a star is older. The gas it formed from hasn't been enriched by as many supernovae and outgassing from PN's over the length of time it was around for, before it formed those stars.