SIMBAD references

By employing as input parameters only observationally determined stellar surface quantities, detailed envelope models for six well-observed luminous blue variables at quiescence are constructed and tested for marginal dynamical instability. The best-observed of these objects, P Cyg, proves to be exactly in a state of marginal dynamical instability, just as predicted. Within the larger observational errors estimated for the five other objects, they too are probably in the same marginally unstable state as P Cyg.