Lecture 25. C. Cepheid Variables

Lecture 25. C. Cepheid Variables

Variables pulsate, contracting and expanding

  1. contraction causes internal pressure increase
  2. pressure increase pushes back on infalling gas, causes rebound
  3. rebounding gas overshoots equilibrium and gravity slows
  4. contraction begins, overshoots equilibrium
  5. goto step 1!

This behavior is "oscillation about equilibrium" -- just like a pendulum!


Brightening Mechanism




Cool Cepheid web page!*

Q: Why aren't Cepheids plotted on H-R diagrams?