# Duration of AGB

1. Nov 17, 2007

### malawi_glenn

Hi!

I have a project where I am supposed to model the s-process in a star in its Helium shell burning region, and i shall do this for a variation of neutron exposure, where neutron exposure are defined as:

$$\tau = N* \Delta t$$ , t is time. N is number density of neutrons.

So I in principle have calculated everything i need, but what is left is that i dont know the times for different mass of stars where they are in the AGB (asymptotic giant branch), it is in the AGB phase where stars have Helium shell burning outside a C and O burning core. So i must find the time duration of those phases.

I have consulted three textbooks. One is Nuclear Physics of stars by Iliadis, one is Stellar structure and evolution by Prianlik, and one is Modern astrophysics by Caroll.

2. Nov 17, 2007

### Chris Hillman

Carroll! :grumpy:

Malawi, I noticed you misspelling the name of Chandrasekhar in another post today, and I hope you will take this to heart: it's not enough to cite your source, you must also spell the authors' names correctly. And if there is more than one, you should not simply omit the other authors! For example, you should cite the book you probably meant as "Bradley W. Carroll and Dale A. Ostlie, An Introduction to Modern Astrophysics, 2nd ed, Addison-Wesley, 2007".

Hope you take this in the spirit suggested--- sounds like you are seriously interested in physics and if so learning to cite properly is part of what you need to learn.

3. Nov 17, 2007

### malawi_glenn

Now i was just asking if anyone has a suggestion for duration time of AGB phase. When writing reports and so on I am very skilled at citing my sources correctly, I promise you.

But writing in a forum like these, I can feel more freeley. And what other astrophysics book have similar name to "Modern astrophysics by Caroll", there is no doubt what sources I have consulted.

Now I have found on wikipedia that AGB lasts for 20 -100 000years, so now I can calculate some ranges for the Neutron exposure. But I really want better sources, so if anyone has it/know it , please contact me. Otherwise I must go through half the city just to get to my astronomy library and search through a lot of books, and the weather in sweden is kinda sucky now =/