# Combined spectroscopy and intensity interferometry to determine the distances of the blue supergiants P Cygni and Rigel

Abstract : In this paper, we report on the spatial intensity interferometry measurements within the H$\alpha$ line on two stars: the Luminous Blue Variable (LBV) supergiant \PCygni\,and the late-type B supergiant Rigel. The experimental setup has been upgraded to allow simultaneous measurement of two polarization channels and the zero baseline correlation function. Combined with simultaneous spectra measurements and based on radiative transfer models calculated with the code CMFGEN, we were able to fit our measured visibility curves to extract the stellar distances. Our distance determinations for both \PCygni\ (1.61 $\pm$ 0.18 kpc) and Rigel (0.26 $\pm$ 0.02 kpc) agree very well with the values provided by astrometry with the Gaia and Hipparcos missions, respectively. This is the first successful step towards extending the application of the Wind Momentum Luminosity Relation method for distance calibration from an LBV supergiant to a more normal late-type B supergiant.
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Preprints, Working Papers, ...
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https://hal.archives-ouvertes.fr/hal-03615887
Contributor : Mathilde Hugbart Connect in order to contact the contributor
Submitted on : Tuesday, March 22, 2022 - 6:01:26 AM
Last modification on : Tuesday, June 21, 2022 - 3:44:17 AM

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### Identifiers

• HAL Id : hal-03615887, version 1
• ARXIV : 2204.00372

### Citation

E. S. G. de Almeida, Mathilde Hugbart, Armando Domiciano de Souza, Jean-Pierre Rivet, Farrokh Vakili, et al.. Combined spectroscopy and intensity interferometry to determine the distances of the blue supergiants P Cygni and Rigel. 2022. ⟨hal-03615887v1⟩

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