AST 341
Homework 4
Due Monday 5 November 2012
C&O questions are from Carroll & Ostlie, 2nd edition (the big orange book).
1. Derive the homologous form of the luminosity equation,
df
dx
= Dp2 tν−2 x2 .
2. C&O 10.3
3. C&O 10.5
4. C&O 10.7
5. C&O 10.17
6. C&O 11.2
7. C&O 11.3
8. T Tauri stars collapse quasi-statically, converting gravitational potential energy
into heat. If you could measure the radius of a T Tauri star very accurately,
how much smaller would it be after a year? Assume a mass of 1 M⊙ , a radius
of 3 R⊙ , and Tef f =4500K. If you had a photometer capable of measuring the
brightness with 0.001 magnitude accuracy, how long would it take before you
noticed the star fading (ignore the fact that all T Tauri stars are stochastically
variable on timescales of days to years)?
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