Some interesting numbers

• Betelgeuse, alpha Orionis, HD39801, HIP27989
• M2 Iab Red Supergiant
• Star with largest apparent diameter
• Hipparcos-distance =131 ± 30 pc
• R=22.1 mas,   R = 620 R_Sun
• M=5 ... 20 M_Sun
• T_eff=3500 ... 3600 K, logg=-0.5 ... 0.5