Betelgeuse: Let numbers talk
- alpha Orionis, HD39801, HIP27989
- M2 Iab Red Supergiant
- Among the stars with largest apparent diameter
- Theta=42 ... 65 mas, R=600 ... 1000 RSun
- Hipparcos-distance =131 ± 30 pc
- M=5 ... 20 MSun
- Teff=3400 ... 3600 K, logg=-0.5 ... 0.5