Nuclear Astrophysics

More documents

Recommendations

Info

A Consistency Check on the Crossover Temperature At the crossover temperature, the energy generation rates of both burning cycles must be equal. So, set For you to show this result for from the equations on page 5 and 6 Many terms cancel on both sides, and we require the temperature to be the same. After cancelling density, mass, and so on, and solving for the common temperature: 36
Luminosity vs Effective Temperature: Hertzsprung-Russel Diagram The previous plot tells us that: For a particular value of luminosity, the pp-chain requires a higher core temperature than does the CNO cycle for stellar masses . We cannot, of course, measure the core temperature of stars, so the previous result would otherwise be only purely theoretical. However, astronomers do measure the effective surface temperatures of stars. Our Main Sequence model should be able to at least quantitatively show the trend of stellar surface temperatures to confirm the previous theoretical result of how the two reaction cycles depend on core temperature and stellar mass. In other words: can the stellar surface temperatures be used to definitively determine where in the Main Sequence stars the pp-chain dominates, and where the CNO-cycle dominates? Let’s work toward the answer to this. Let the data tell us how the nuclear reactions in the core are connected to the temperature and luminosity we observe from the stars. 37
Page 1 and 2: Nuclear Astrophysics Lecture 9 &10
Page 3 and 4: We have (again) Set the argument of
Page 5 and 6: Let’s pull out the physics of thi
Page 7 and 8: Finally, recall 7
Page 9 and 10: Examples: The core of our Sun has a
Page 11 and 12: Reaction Rate: Temperature Dependen
Page 13 and 14: Using the equations on previous sli
Page 15 and 16: Finally, then, we have that the mas
Page 17 and 18: The power series expansion of , for
Page 19 and 20: Structure of Polytrope Sun Let us d
Page 21 and 22: Derivative of Luminosity 21
Page 23 and 24: Arbitrary Units Standard Solar Mode
Page 25 and 26: Proton-Proton-Chain p + p d + e +
Page 27 and 28: The nuclear energy production in Ma
Page 29 and 30: PP-Chain Nuclear Energy Rate vs Cor
Page 31 and 32: The power per unit mass produced in
Page 33 and 34: From page 15, Lecture 6, the Main S
Page 35: Main Sequence: Core Temperature vs
Page 39 and 40: We have a first “hint” here of
Page 41 and 42: Main Sequence: Luminosity vs Effect
Page 43 and 44: Hertzprung-Russel Diagram CNO Cycle
Page 45 and 46: Integrated Luminosity Let us take 9
Page 47 and 48: Mass Interior to Radius Mass contai
Page 49: Nuclear Generation Rate Using the p

Nuclear Astrophysics

Create successful ePaper yourself

Delete template?

Save as template?