Observations of the pulsation of the Cepheid l Car with the Sydney University Stellar Interferometer

Abstract

Observations of the southern Cepheid l Car to yield the mean angular diameter and angular pulsation amplitude have been made with the Sydney University Stellar Interferometer (SUSI) at a wavelength of 696 nm. The resulting mean limb-darkened angular diameter is 2.990+-0.017 mas (i.e. +-0.6 per cent) with a maximum-to-minimum amplitude of 0.560+-0.018 mas corresponding to 18.7+-0.6 per cent in the mean stellar diameter. Careful attention has been paid to uncertainties, including those in measurements, in the adopted calibrator angular diameters, in the projected values of visibility squared at zero baseline, and to systematic effects. No evidence was found for a circumstellar envelope at 696 nm. The interferometric results have been combined with radial displacements of the stellar atmosphere derived from selected radial velocity data taken from the literature to determine the distance and mean diameter of l Car. The distance is determined to be 525+-26 pc and the mean radius 169+-8R{solar). Comparison with published values for the distance and mean radius show excellent agreement, particularly when a common scaling factor from observed radial velocity to pulsation velocity of the stellar atmosphere (the p-factor) is used.

arXiv comment12 pages, 5 figures, accepted by MNRAS

References in corpus (18)

• Hubble Space Telescope Fine Guidance Sensor Parallaxes of Galactic Cepheid Variable Stars: Period-Luminosity Relations
• Astrometry with Hubble Space Telescope: A Parallax of the Fundamental Distance Calibrator delta Cephei
• A catalogue of [Fe/H] determinations : 1996 edition
• Cepheid Parallaxes and the Hubble Constant
• The effect of metallicity on the Cepheid Period-Luminosity relation from a Baade-Wesselink analysis of Cepheids in the Galaxy and in the Small Magellanic Cloud
• High resolution spectroscopy for Cepheids distance determination. I. Line asymmetry
• Cepheid distances from infrared long-baseline interferometry - I. VINCI/VLTI observations of seven Galactic Cepheids
• High resolution spectroscopy for Cepheids distance determination. III. A relation between gamma-velocities and gamma-asymmetries
• High resolution spectroscopy for Cepheids distance determination. II. A period- projection factor relation
• Extended envelopes around Galactic Cepheids III. Y Oph and alpha Per from near-infrared interferometry with CHARA/FLUOR
• Very accurate Distances and Radii of Open Cluster Cepheids from a Near-Infrared Surface Brightness Technique
• Fundamental parameters of Cepheids. V. Additional photometry and radial velocity for southern Cepheids
• Long baseline interferometric observations of Cepheids
• The angular size of the Cepheid L Car: a comparison of the interferometric and surface brightness techniques
• Theoretical Limb Darkening for Pulsating Cepheids
• Theoretical Limb Darkening for Classical Cepheids: II. Corrections for the Geometric Baade-Wesselink Method
• Infrared Surface Brightness Distances to Cepheids: a comparison of Bayesian and linear-bisector calculations
• The Sydney University Stellar Interferometer: A Major Upgrade to Spectral Coverage and Performance

Cited by in corpus (11)

• 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
• Investigating Cepheid $\ell$ Carinae's Cycle-to-cycle Variations via Contemporaneous Velocimetry and Interferometry
• Observational calibration of the projection factor of Cepheids IV. Period-projection factor relation of Galactic and Magellanic Cloud Cepheids
• CORS Baade-Wesselink method in the Walraven photometric system: the Period-Radius and the Period-Luminosity relation of Classical Cepheids
• Mean angular diameters, distances and pulsation modes of the classical Cepheids FF Aql and T Vul - CHARA/FLUOR near-infrared interferometric observations
• Analysing the spectral energy distributions of Galactic classical Cepheids
• Stellar Intensity Interferometry: Prospects for sub-milliarcsecond optical imaging
• VEGA/CHARA interferometric observations of Cepheids. I. A resolved structure around the prototype classical Cepheid delta Cep in the visible spectral range
• CRIRES high-resolution infrared spectroscopy of the long-period Cepheid l Car
• Abundance analysis of the supergiant stars HD 80057 and HD 80404 based on their UVES Spectra