Intensity interferometry of P Cygni in the H$\alpha$ emission line: towards distance calibration of LBV supergiant stars

Abstract : We present intensity interferometry of the luminous blue variable P Cyg in the light of its H$\alpha$ emission performed with 1 m-class telescopes. We compare the measured visibility points to synthesized interferometric data based on the CMFGEN physical modeling of a high-resolution spectrum of P Cyg recorded almost simultaneously with our interferometry data. Tuning the stellar parameters of P Cyg and its H$\alpha$ linear diameter we estimate the distance of P Cyg as $1.56\pm0.25$ kpc, which is compatible within $1\sigma$ with $1.36\pm0.24$ kpc reported by the Gaia DR2 catalogue of parallaxes recently published. Both values are significantly smaller than the canonic value of $1.80\pm0.10$ kpc usually adopted in literature. Our method used to calibrate the distance of P Cyg can apply to very massive and luminous stars both in our galaxy and neighbour galaxies and can improve the so-called Wind-Momentum Luminosity relation that potentially applies to calibrate cosmological candles in the local Universe.
Document type :
Journal articles

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Submitted on : Wednesday, October 30, 2019 - 8:55:59 PM
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Citation

J. -P. Rivet, A. Siciak, E. S. G. de Almeida, F. Vakili, A. Domiciano de Souza, et al.. Intensity interferometry of P Cygni in the H$\alpha$ emission line: towards distance calibration of LBV supergiant stars. Monthly Notices of the Royal Astronomical Society, Oxford University Press (OUP): Policy P - Oxford Open Option A, 2020, 494, pp.218. ⟨10.1093/mnras/staa588⟩. ⟨hal-02340533⟩

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