English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Plus monthly

Global: Zendy Tools annual

Global: Zendy Tools monthly

Global: Zendy Free Plan

In this paper we report on spatial intensity interferometry measurementswithin the H$\alpha$ line on two stars: the Luminous Blue Variable supergiant\PCygni\,and the late-type B supergiant Rigel. The experimental setup wasupgraded to allow simultaneous measurement of two polarization channels,instead of one in our previous setup, and the zero baseline correlationfunction on-sky to validate independent estimates obtained from the stellarspectrum and the instrumental spectral throughput. Combined with simultaneousspectra measurements and based on radiative transfer models calculated with thecode CMFGEN, we were able to fit our measured visibility curves to extract thestellar 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 valuesprovided by astrometry with the Gaia and Hipparcos missions, respectively. Thisresult for Rigel was obtained by adopting a stellar luminosity of $L_{\star}$ =123000 $L_{\odot}$, which is reported in the literature as being consistentwith the Hipparcos distance to Rigel. However, due to the lack of consensus onRigel's luminosity, we also explore how the adoption of the stellar luminosityin our models affects our distance determination for Rigel. In conclusion, wesupport, in an independent way, the distance to Rigel as the one provided bythe Hipparcos mission, when taking the luminosity of 123000 $L_{\odot}$ at facevalue. This study is the first successful step towards extending theapplication of the Wind Momentum Luminosity Relation method for distancecalibration from an LBV supergiant to a more normal late-type B supergiant.

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