View Full Version : Stellar formation and evolution
RedAether
Dec30-10, 11:35 AM
I know the general accepted theory to the birth of our solar system. One or more nearby stars went supernova and the shock waves caused our gas cloud to collapse forming our solar system. However, i wanted an opinion from those with more knowledge on a hypothesis that seems to make some sense to me.
Could it be possible for a large star to go supernova/nova, and then the remaining core to accrete a new atmosphere from the remains and reignite as a smaller, more stable star? It would seem to me that it would be difficult for our solar system to accumulate the heavy elements that we have just from accepting blown out bits from nearby supernovas. However, if a star underwent a smallish nova early in life and then reignited as a smaller star there would be plenty of material for rocky planet formation like we have now.
Thoughts? I could easily be way off, and would really appreciate any critical comments.
NobodySpecial
Dec30-10, 12:27 PM
One or more nearby stars went supernova and the shock waves caused our gas cloud to collapse forming our solar system.
I don't think the SN is necessary for the gas cloud to collapse - gas clouds pretty much collapse anyway. A lot of the SN theories were the idea that there was something rare and special needed to create our solar system - often promoted by people with a certain creation myth. We now know that solar systems and planets are very common.
Could it be possible for a large star to go supernova/nova, and then the remaining core to accrete a new atmosphere from the remains and reignite as a smaller, more stable star?
A SN is pretty violent. A large star will create a black hole, a smaller progenitor creates a neutron star. There is a class of giant stars that escape the SN fate by expelling a large part of their atmosphere late in their life and ending up as smaller cooler dwarfs
It would seem to me that it would be difficult for our solar system to accumulate the heavy elements that we have just from accepting blown out bits from nearby supernovas.
The early stars in the galaxy were massive low metal stars with very short lives (few 100Myr) that went SN. There were many generations of these before metal rich stars like our sun were formed.
Remember you only need a SN for elements heavier than iron - regular large stars produce the carbon,oxygen, silicon, magnesium that our planet is made from
RedAether
Dec30-10, 01:09 PM
Thanks for the reply. I guess I would like to clarify my basic question. I do understand that SNs create nearly all of the heavy elements, and that before our sun was born many generations of young stars died violent deaths creating a bunch of heavy elements.
However, what i am really trying to get at is this: Is it possible that our sun (or any similar metal rich star like our own) is a direct remnant from a previous small nova event? Or would even a small nova prevent (or destroy) planetary formation around that star?
RedAether
Dec30-10, 01:21 PM
The current model of stellar birth is fairly peaceful (you know besides all the accretion disks and fusion ignition going on). Is there any evidence (for or against) small stellar explosions early in their life cycles?
Is it possible that our sun (or any similar metal rich star like our own) is a direct remnant from a previous small nova event?
Read up on nova events.
Those happen if you "accrete a new atmosphere [...] and reignite". What you get is not really "a smaller, more stable star". You get a nova.
Kracatoan
Dec30-10, 04:50 PM
I don't think the left-over core of a supernova can accumulate enough gas from the explosion remnants to fully reignite - the explosion would have blown them too far away.
However, with binary star systems, it is strongly believed that if one star dies and leaves behind a white dwarf, it can accumulate mass from the other star and then reignite. There are many different versions of this scenario, involving different stellar pairings in the binary, all of which would act differently, I think one combination is believed to be responsible for gamma ray bursts, I think one of the stars has to be a neutron star and the other a red giant, but I don't know for sure.
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