Planetary and stellar evolution

[Dilberth]

My question for the community is this:   Could a star, after it has gone off the main sequence,  contract violently and produce a supernova, and then, during this event, produce the remainder of the elements, bypassing iron, since that element was already synthesized by the triple-alpha process or even the CNO process? Is it possible for this supernova to slowly die as a chunk of coal dies in a blast furnace becoming, more or less, a planet with U-238 at the core? This particular star  would be an F or G spectral class.  In effect, what I'm postulating is that some stars contain the exact mass/luminosity ratio to produce a planet as the end result. Yes, this is a bit outside of the box. Anyone care to respond?

 

[UFmbutler]

<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>My question for the community is this:&nbsp;&nbsp; Could a star, after it has gone off the main sequence,&nbsp; contract violently and produce a supernova, and then, during this event, produce the remainder of the elements, bypassing iron, since that element was already synthesized by the triple-alpha process or even the CNO process? Is it possible for this supernova to slowly die as a chunk of coal dies in a blast furnace becoming, more or less, a planet with U-238 at the core? This particular star&nbsp; would be an F or G spectral class.&nbsp; In effect, what I'm postulating is that some stars contain the exact mass/luminosity ratio to produce a planet as the end result. Yes, this is a bit outside of the box. Anyone care to respond? <br /> Posted by Dilberth</DIV></p><p>&nbsp;</p><p>I don't think any ratio of mass to luminosity will produce a planet...physics dictates that there are only a few possible end results following a supernova, and none of them are as small or stable as a planet.&nbsp; It's really not possible when you think of it...even if the core turned into say, a huge(>10 jupiter mass) planet it would start accreting the surrounding gas, and there is going to be a ton of this gas, so eventually it would turn into a brown dwarf/regular star again.&nbsp; Now, supernovae can trigger star formation by shocking the surrounding gas, but not like this.&nbsp; It's interesting to think of but impossible. &nbsp; </p> <div class="Discussion_UserSignature"> </div>