SIMBAD references

High spatial resolution observations of the Hα-emitting wind structure associated with the luminous blue variable star P Cygni were obtained with the Navy Prototype Optical Interferometer. These observations represent the most comprehensive interferometric data set on P Cyg to date. We demonstrate how the apparent size of the Hα-emitting region of the wind structure of P Cyg compares between the 2005, 2007, and 2008 observing seasons and how this relates to the Hα line spectroscopy. Using the data sets from 2005, 2007, and 2008 observing seasons, we fit a circularly symmetric Gaussian model to the interferometric signature from the Hα-emitting wind structure of P Cyg. Based on our results, we conclude that the radial extent of the Hα-emitting wind structure around P Cyg is stable at the 10% level. We also show how the radial distribution of the Hα flux from the wind structure deviates from a Gaussian shape, whereas a two-component Gaussian model is sufficient to fully describe the Hα-emitting region around P Cyg.