International audience
Context. The Baade-Wesselink (BW) method, which combines linear and angular diameter variations, is the most common method to determine the distances to pulsating stars. However, the projection factor, p-factor, used to convert radial velocities into pulsation velocities, is still poorly calibrated. This parameter is critical on the use of this...
International audience
Aims. We aim to investigate the infrared excess of 45 Milky Way (MW) Cepheids combining different observables in order to constrain the presence of circumstellar envelopes (CSEs). Methods. We used the SpectroPhoto-Interferometry of Pulsating Stars (SPIPS) algorithm, a robust implementation of the parallaxof-pulsation method that combines...
Cepheids are the keystone of the extragalactic distance ladder since their pulsation periods correlate directly with their luminosity, through the Period-Luminosity (PL) relation (Leavitt & Pickering 1912). The discovery of the accelerated expansion of the Universe (Riess et al. 1998; 2011 Nobel prize) is largely based on the Cepheid distance...
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. It has recently been shown that the infrared (IR) emission of Cepheids, constant over the pulsation cycle, might be due to a pulsating shell of ionized gas with a radius of about 15% of that of the star radius, which could be attributed to the chromospheric activity of Cepheids. Aims. The aim of this paper is to investigate the...
International audience
Our sample is made up of 64 Classical Galactic Cepheids with pulsation periods in the range 2 to 68 days. We provide the full details of our sample in Table A.1. We present both the six correlation templates built to derive tailored cross-correlation functions (CCFs), the CCFs themselves, and the derived radial velocity and line profile...
International audience
International audience