particle era; era of atoms; nucleosynthesis; nuclei; galaxies C.
Figure 7: Schematic diagram of Li evolution in the universe
The vertical axis shows the number ratio of Li and H. The horizontal axis shows the amount of heavy elements (ratio to solar abundance). The farther to the right a star lies in the diagram, the more heavy elements it has and the younger it is. The curve in the diagram presents the upper envelope of the observed Li abundance [Reference : ]. To explain the shape of this curve, scientists assume that there are three sources for Li production: (1) nucleosynthesis in the Big Bang (should be a constant in the diagram = ), (2) Li production in objects or events originating from massive stars (e.g. supernova explosions, spallation of nuclei triggered by galactic cosmic rays), which begins its contribution in the early universe (), and (3) Li production in low-mass (=longer lifetime) stars (e.g. nova explosions), which begins in the recent universe, where the amount of heavy elements exceeds 10 percent of the solar value (). In particular, the contribution of the third component must be dominant in the current universe, though scientists have been unable to get any signs of Li production in low-mass stellar components. (Credit : NAOJ)
So, when this first wave of nucleosynthesis was completed.
Nucleosynthesis and Data Visualisation Peter James Thomas SlideShare Horizontal Toast in Thick x in Wide x in Length Solid Bamboo Flooring sq ft case Legends Flooring and Home
Earlier in its lifetime, the star began fusing hydrogen and helium in its core into heavier elements through the process known as "." The energy made by the fusion of heavier and heavier elements balanced the star against the force of gravity. These reactions continued until they formed iron in the core of the star. At this point, further nucleosynthesis would consume rather than produce energy, so gravity then caused the star to implode and form a dense stellar core known as a neutron star.
107: Nucleosynthesis: Elements from Stars.
As space expanded, temperatures dropped below those required to sustain fusion, and as a result nucleosynthesis only lasted for about three minutes. A third of the atomic hydrogen was converted into helium and no elements heavier than lithium could synthesize.
r-Process Nucleosynthesis Shinya Wanajo (Univ.
A team of astronomers from National Astronomical Observatory of Japan (NAOJ), Osaka Kyoiku University, Nagoya University, and Kyoto Sangyo University observed Nova Delphini 2013 (, ) which occurred on August 14, 2013. Using the 8.2-meter Subaru Telescope High Dispersion Spectrograph (HDS) to observe this object, they discovered that the outburst is producing a large amount of lithium (Li; ). Lithium is a key element in the study of the chemical evolution of the universe because it likely was and is produced in several ways: through Big Bang nucleosynthesis, in collisions between energetic cosmic rays and the interstellar medium, inside stellar interiors, and as a result of novae and supernova explosions. This new observation provides the first direct evidence for the supply of Li from stellar objects to the galactic medium. The team hopes to deepen the understandings of galactic chemical evolution, given that nova explosions must be important suppliers of Li in the current universe.
Nucleosynthesis of gold in the lab Oct 18, 2012 #1.
Figure 2: Nucleosynthesis in the universe
Heavy elements such as C, O, and Fe are mainly produced in stellar interior and/or supernova. On the other hand, Li might be produced in many other ways: in the Big Bang, galactic cosmic ray collisions. Li production in stellar originating objects has not been confirmed yet by observations, as designated by "?" marks. (Credit : NAOJ)
NASA's Cosmicopia - Basics - Composition - Nucleosynthesis
This type of situation where an intermediate product is the weak link in the overall synthesis is sometimes called a "bottleneck." This concept also applies in nucleosynthesis of heavier elements.