Where can I find info on how stars create the whole periodic table of elements?

Question

I know the basics (H to He...to Fe), but I've never seen an explanation showing the origin of every single element, or anything with an atomic # beyond iron.

Answer 1

Supernovae are the "furnaces" in which the heavier metals are forged (fused and nucleo-synthesised).

The Big Bang produced hydrogen, helium, and traces of lithium, while all heavier elements are synthesized in stars and supernovae.

Supernovae are the main source of all the elements heavier than oxygen. These elements are produced by fusion (for iron fifty-six, 56Fe, and lighter elements), and by nucleosynthesis during the supernova explosion for elements heavier than iron.

The only competing process for producing elements heavier than iron is the s-process in large, old red giant stars, which produces these elements much more slowly, and which cannot produce elements heavier than lead.

Supernovae inject these heavy elements into the interstellar medium, ultimately enriching the molecular clouds that are the sites of star formation.

Evidence from daughter products of short-lived radioactive isotopes shows that a nearby supernova helped determine the composition of the Solar System 4.5 billion years ago. Supernova production of heavy elements over astronomic periods of time ultimately made the chemistry of life on Earth possible.

THE S-PROCESS:

The s-process or slow-neutron-capture-process is a nucleosynthesis process that occurs at lower neutron density, lower temperature conditions in stars.

Under these conditions the rate of neutron capture by atomic nuclei is slow relative to the rate of radioactive beta-decay. This process produces stable isotopes by moving along the valley of beta stability in the chart of isotopes.

The s-process produces approximately half of the elements heavier than iron, and therefore plays an important role in the galactic chemical evolution.

The s-process is believed to occur in stars more massive than Earth's sun, most notably Asymptotic Giant Branch stars.

In contrast to the r-process which is believed to occur over time scales of seconds in explosive environments, the s-process is believed to occur over time scales of thousands of years.

The extent to which the s-process moves up the elements in the chart of isotopes to higher mass numbers is essentially determined by the degree to which the star in question is able to produce neutrons, and by the amount of iron in the star's initial abundance distribution. Iron is the "starting material" (or seed) for this neutron capture - beta decay sequence of synthesizing new elements.

The S-process does not have the ability to produce any of the heavy radioactive isotopes such as Thorium or Uranium. It goes no further than lead. The cycle that terminates the S-process is:

209Bi + n0 → 210Bi + γ
210Bi → 210Po + β-
210Po → 206Pb + α

Pb-206 then captures three neutrons, producing Pb-209, which decays to Bi-209 by beta decay, restarting the cycle.

THE R-PROCESS:

The R-process (R for rapid) is a neutron capture process for radioactive elements which occurs in high neutron density, high temperature conditions.

Contrast with P- and S-processes. In the R-process nuclei are bombarded with a large neutron flux to form highly unstable neutron rich nuclei which very rapidly decay to form stable neutron rich nuclei.

The site of the R-process is believed to be iron-core collapse supernovae, which provide the necessary physical conditions for the R-process.

Due to the much higher neutron flux in this process (on the order of 10^22 neutrons per cm^2 per second), the rate of isotopic formation is much faster than the beta decays which follow,

the R-process terminates when the nuclei synthesised become readily unstable to spontaneous fission (currently believed to be in the region of Atomic Weight = 270 - or roughly in the Rutherfordium - Darmstadtium area of the periodic table).

Rutherfordium has the symbol Rf and atomic number 104. Its most stable isotope is 265Rf with a half-life of approximately 13 hours;

Darmstadtium has the symbol Ds and atomic number 110. its isotopes of mass 267 to 273 have half-lives measured in microseconds. Heavier isotopes, of mass 279 and 281 are more stable, with half-lives of 180 milliseconds and 11.1 seconds, respectively.

Fissile decay chains will then lead back to Thorium and Uranium.

I have supplied links re the P-process and Rp-process.

Answer 2

There is a great book called E=MC^2, a biography of the world's most famous equation. There is a lot of stuff you don't need to know in there, but it has a pretty good explanation of how fusion works.

Answer 3

Hahaha loved both definitions of these elements. your on a roll tonight my friend thx for the laugh star

Answer 4

all the elements on earth comes from stars

Answer 5

Here is a website that describes the cycle that lead to the highest masses.

Aloha

Answer 6

You should read the book:"Stardust" by John Gribben. It is really great.