Mean angular diameters, distances and pulsation modes of the classical Cepheids FF Aql and T Vul - CHARA/FLUOR near-infrared interferometric observations

Abstract

We report the first angular diameter measurements of two classical Cepheids, FF Aql and T Vul, that we have obtained with the FLUOR instrument installed at the CHARA interferometric array. We obtain average limb-darkened angular diameters of θ_LD = 0.878 +/- 0.013 mas and θ_LD = 0.629 +/- 0.013 mas, respectively for FF Aql and T Vul. Combining these angular diameters with the HST-FGS trigonometric parallaxes leads to linear radii R = 33.6 +/- 2.2 Rsol and R = 35.6 +/- 4.4 Rsol, respectively. The comparison with empirical and theoretical Period-Radius relations leads to the conclusion that these Cepheids are pulsating in their fundamental mode. The knowledge of the pulsation mode is of prime importance to calibrate the Period-Luminosity relation with a uniform sample of fundamental mode Cepheids.

References in corpus (4)

• Calibrating the Cepheid Period-Luminosity relation from the infrared surface brightness technique I. The p-factor, the Milky Way relations, and a universal K-band relation
• Extended envelopes around Galactic Cepheids III. Y Oph and alpha Per from near-infrared interferometry with CHARA/FLUOR
• Thermal infrared properties of classical and type II Cepheids Diffraction limited 10 microns imaging with VLT/VISIR
• Observations of the pulsation of the Cepheid l Car with the Sydney University Stellar Interferometer

Cited by in corpus (15)

• Gaia Data Release 1. Testing the parallaxes with local Cepheids and RR Lyrae stars
• Baade-Wesselink distances to Galactic and Magellanic Cloud Cepheids and the effect of metallicity
• Observational calibration of the projection factor of Cepheids. II. Application to nine Cepheids with HST/FGS parallax measurements
• Spherically-symmetric model stellar atmospheres and limb darkening I: limb-darkening laws, gravity-darkening coefficients and angular diameter corrections for red giant stars
• Observational calibration of the projection factor of Cepheids IV. Period-projection factor relation of Galactic and Magellanic Cloud Cepheids
• Multiplicity of Galactic Cepheids from long-baseline interferometry. IV. New detected companions from MIRC and PIONIER observations
• Fundamental properties of red-clump stars from long-baseline H-band interferometry
• Analysing the spectral energy distributions of Galactic classical Cepheids
• Consistent radial velocities of classical Cepheids from the cross-correlation technique
• Towards reliable uncertainties in IR interferometry: The bootstrap for correlated statistical & systematic errors
• Extended envelopes around Galactic Cepheids. V. Multi-wavelength and time-dependent analysis of IR excess
• Updated 24 $\mu \mathrm{m}$ Period-Luminosity Relation Derived from Galactic Cepheids
• Probing the innermost region of the AU~Microscopii debris disk
• The Pulsation Mode and Distance of the Cepheid FF Aquilae
• Cepheid distances from the Baade-Wesselink method