Third-generation star

Our planet Earth contains significant amounts of elements all the way up to Z = 92. This indicates that our solar system resulted from the gravitational collapse of a cloud of matter that included debris from second-generation stellar supemovae. Thus, our sun most likely is a third-generation star. The composition of a third-generation star includes high-Z nuclides, but the nuclear reactions are the same as those in a second-generation star. 

C22-0073. Second- and third-generation stars may contain significant amounts of carbon yet carbon burning does not begin until the third stage of their evolution. Explain this. 

The second generation of stars, called population II stars, was comprised of hydrogen, helium, and about 1% of the heavier elements such as carbon and oxygen. Finally, there was a third generation of stars, like our sun, called population I stars. These stars consist of hydrogen, helium, and 2-5% of the heavier elements. 

L.M. Sherman, Third Generation Blowing Agents Starred at Polyurethanes 95, Plast. Tech-nol. 41, 25, Oct. (1995). 

Equation 1. Third-generation (16 Ru atoms) mthenium-benzylidene dendrimer that catalyzes the ROMP of norbomene at 25°C to form dendrimer-cored stars. With 100 norbomene units on each branch, the polymerization is living (i.e. can be continued by adding more norbomene)... 

In order to clarify the stmctures of dendrimer-Uke star-branched polymers, the representative third-generation (3G) and fifth-generation (5G) polymers are shown in Figure 5.1. As can be seen, these polymers are structurally well defined and similar in branched architecture to dendrimers, but are composed of many polymer chains linked to each other between the junctions in aU generations. Accordingly, they are much higher in molecular weight and much... 

In 1938 Bethe formulated the mechanism for energy generation in stars. This research grew out of his participation at the third Washington conference on theoretical physics in April 1938. The reaction... 

The Discovery of the Fullerenes. In experiments carried out at Rice University in 1985 associated with the presence of carbon in stars and space [Kroto HW, Heath JR, O Brien SC, Curl RF, Smalley RE (1985) Nature 318 162], the Ceo molecule was discovered. This species is one of the many carbon clusters which can be generated when a plasma of carbon vapor produced in the surface of graphite by laser irradiation is cooled by an inert gas jet. The detection of this type of carbon aggregate which appears to constitute a third allotropic and the first molecular form of carbon by mass spectroscopy is illustrated in Fig. 4.18. 

---