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Last name: GRACZYK
First name: D.
International audience
International audience
Context. Surface brightness-color relations (SBCRs) are widely used for estimating angular diameters and deriving stellar properties. They are critical to derive extragalactic distances of early-type and late-type eclipsing binaries or, potentially, for extracting planetary parameters of late-type stars hosting planets. Various SBCRs have been...
Observations of 48 red-clump stars were obtained in the H band with the PIONIER instrument installed at the Very Large Telescope Interferometer. Limb-darkened angular diameters were measured by fitting radial intensity profile I(r) to square visibility measurements. Half the angular diameters determined have formal errors better than 1.2%,...
International audience
International audience
Context. The projection factor p is the key quantity used in the Baade-Wesselink (BW) method for distance determination; it converts radial velocities into pulsation velocities. Several methods are used to determine p, such as geometrical and hydrodynamical models or the inverse BW approach when the distance is known. Aims. We analyze new...
We extended the sample of 35 eclipsing binaries compiled by Graczyk+ (2017ApJ...837....7G) by searching for detached systems in the literature suitable for a precise distance determination. Our sample contains 81 systems (51 on the northern hemisphere and 30 on the southern one). Their basic parameters are presented in Table 1. We used Tycho-2...
Context. The surface brightness – color relationship (SBCR) is a poweful tool for determining the angular diameter of stars from photometry. It was for instance used to derive the distance of eclipsing binaries in the Large Magellanic Cloud (LMC), which led to its distance determination with an accuracy of 1%.Aims. We calibrate the SBCR for red...
International audience
Context. The dynamical structure of the atmosphere of Cepheids has been well studied in the optical. Several authors have found very interesting spectral features in the J band, but little data have been secured beyond 1.6 μm. However, such observations can probe different radial velocities and line asymmetry regimes, and are able to provide...
International audience
International audience
International audience
Context. The Baade-Wesselink (BW) method of distance determination of Cepheids is used to calibrate the distance scale. Various versions of this method are mainly based on interferometry and/or the surface-brightness color relation (SBCR). Aims. We quantify the impact of the SBCR, its slope, and its zero point on the projection factor. This...
In the last 20 years, over the course of the Araucaria project, we have studied 20 very special eclipsing binary systems in the Large Magellanic Cloud (LMC). Based on these systems and our newly calibrated surface brightness-colour relation we have measured a distance to the LMC that is accurate to 1%. This is currently the best benchmark for...
International audience
International audience
Aims. Surface brightness – colour relations (SBCRs) are very useful tools for predicting the angular diameters of stars. They offer the possibility to calculate very precise spectrophotometric distances by the eclipsing binary method or the Baade-Wesselink method. Double-lined Detached Eclipsing Binary stars (SB2 DEBs) with precisely known...