The Spatially Resolved H\alpha-Emitting Wind Structure of P Cygni

TL;DR

This study uses high-resolution interferometric observations to analyze the size and structure of P Cygni's H extalpha-emitting wind, revealing stability over multiple years and a complex flux distribution.

Contribution

First comprehensive interferometric analysis of P Cygni's wind structure, demonstrating stability and detailed flux distribution modeling over several years.

Findings

H extalpha-emitting region size stable within 10% over years

Radial flux distribution deviates from a simple Gaussian shape

Two-component Gaussian model fits the wind structure well

Abstract

High spatial resolution observations of the H\alpha-emitting wind structure associated with the Luminous Blue Variable star P Cygni were obtained with the Navy Prototype Optical Interferometer (NPOI). These observations represent the most comprehensive interferometric data set on P Cyg to date. We demonstrate how the apparent size of the H\alpha-emitting region of the wind structure of P Cyg compares between the 2005, 2007 and 2008 observing seasons and how this relates to the H\alpha 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 H\alpha-emitting wind structure of P Cyg. Based on our results we conclude that the radial extent of the H\alpha-emitting wind structure around P Cyg is stable at the 10% level. We also show how the radial distribution of the H\alpha flux from the wind structure deviates from a Gaussian shape, whereas a two-component Gaussian model is sufficient to fully describe the H\alpha-emitting region around P Cyg.