Granulation in Supergiants
- There are large cells (global long-lived + small short-lived).
- Schwarzschild's scaling arguments were OK, only Sun is not a good reference.
- Better correspondence: stars with more efficient radiation:
- stars near the "granulation boundary":
- Cepheids, A-type stars with inverse bisectors (Gray 2008)
- Reason for relatively large cells:
- Bifurcation of cell sizes
- Pressure scale height below the surface
- Sphericity effects
Consequences for RHD Simulations
- Basic mechanism that drives atmospheric flows is no longer certain.
- Our benchmark star, the Sun, is no longer useful. We need new references.