Naked Science Forum

Non Life Sciences => Chemistry => Topic started by: Mad Mark on 04/02/2012 20:24:47

Title: How do stars create atoms of other elements?
Post by: Mad Mark on 04/02/2012 20:24:47

Please can some one clear up a few questions about Atoms being created in the core of a star please.
Does a star create the elements in its core in layers with the latest and heaviest in the centre?
When creating an element like Carbon is it combining 2 atoms of Lithium or 6 atoms of Hydrogen or one atom of Boron and one atom of Hydrogen?
Why is Mercury more abundant than Gold if Mercury came after in an exploding star.

Title: Re: Creating atoms?
Post by: damocles on 13/02/2012 04:23:44

The formation of atoms in the nuclear reactions in stars involves some quite complex mechanisms. To get a proper answer you would really need to do quite a lot of reading.

A few short and simple answers: carbon in particular, and similar "light atoms" are produced in nuclear reactions in the core of stars. Only atoms with atomic number less than iron, or possibly nickel, can be made in this way. Heavier atoms are much less abundant, and are formed mainly (only?) in supernova explosions.

Atoms with even atomic number are more stable (lower energy) and more abundant than those with odd atomic number. Even number elements can have as many as 8 or 10 stable isotopes; odd number elements have only 1 or 2. Throughout  the periodic table, the cosmic abundance of elements is, generally speaking, a zigzag line with peaks at even number elements and dips at odd number elements.

Carbon is formed in a catalytic cycle; it is effectively formed from 3 helium atoms, but the mechanism is much more complicated than 3 helium atoms coming together. Lithium, beryllium, and boron have much lower cosmic abundance than carbon, nitrogen, and oxygen, and only enter into the carbon production process in a very transitory way.

The nuclear processes that form elements heavier than helium are fairly well understood, but there is still some uncertainty -- it is enormously difficult to observe precisely what is happening in the core region of any star, even our own sun.

If you want to go deeper into this stuff, try:
http://hyperphysics.phy-astr.gsu.edu/hbase/astro/astfus.html (http://hyperphysics.phy-astr.gsu.edu/hbase/astro/astfus.html)
http://en.wikipedia.org/wiki/Star#Nuclear_fusion_reaction_pathways (http://en.wikipedia.org/wiki/Star#Nuclear_fusion_reaction_pathways)
http://www.astrophysicsspectator.com/topics/stars/Fusion.html (http://www.astrophysicsspectator.com/topics/stars/Fusion.html)

Title: Re: How do stars create atoms of other elements?
Post by: Mad Mark on 14/02/2012 23:28:10

Thank you for that information, going to do some reading up on this.

Title: Re: How do stars create atoms of other elements?
Post by: Satoyaki on 18/02/2012 23:57:55

its part of the nature of light. it is in lights nature to create. any light that exists, when stimulated will produce more light through a chemical reaction, like a cell dividing.