Intensity interferometry of P Cygni in the H α 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 α emission performed with 1 m-class telescopes. We compare the measured visibility points to synthesized interferometric data based on the CMFGEN physical modelling 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 α linear diameter, we estimate the distance of P Cyg as 1.56 ± 0.25 kpc, which is compatible within 1σ with 1.36 ± 0.24 kpc reported by the Gaia DR2 catalogue of parallaxes recently published. Both the values are significantly smaller than the canonic value of 1.80 ± 0.10 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 neighbouring galaxies, and can improve the so-called wind momentum-luminosity relation that potentially applies to calibrate cosmological candles in the local Universe.
- Publication:
-
Monthly Notices of the Royal Astronomical Society
- Pub Date:
- May 2020
- DOI:
- 10.1093/mnras/staa588
- arXiv:
- arXiv:1910.08366
- Bibcode:
- 2020MNRAS.494..218R
- Keywords:
-
- techniques: interferometric;
- stars: distances;
- stars: massive;
- stars: winds;
- outflows;
- Astrophysics - Instrumentation and Methods for Astrophysics;
- Astrophysics - Solar and Stellar Astrophysics
- E-Print:
- To be published in MNRAS