Tests of stellar model atmospheres by optical interferometry IV: VINCI interferometry and UVES spectroscopy of Menkar

Abstract

We present K-band interferometric and optical spectroscopic observations of Menkar obtained with the instruments VINCI and UVES at Paranal Observatory. Spherically symmetric PHOENIX stellar model atmospheres are constrained by comparison to our interferometric and spectroscopic data, and high-precision fundamental parameters of Menkar are obtained. Our high-precision VLTI/VINCI observations in the first and second lobes of the visibility function directly probe the model-predicted strength of the limb darkening effect in the K-band and the stellar angular diameter. The high spectral resolution of UVES allows us to confront observed and model-predicted profiles of atomic lines and molecular bands. We show that our derived PHOENIX model atmosphere for Menkar is consistent with both the measured strength of the limb-darkening in the near-infrared K-band and the profiles of spectral bands around selected atomic lines and TiO bandheads. At the detailed level of our high spectral resolution, however, noticeable discrepancies between observed and synthetic spectra exist. We obtain a Rosseland angular diameter of Theta_Ross=12.20 mas pm 0.04 mas. Together with the Hipparcos parallax, it corresponds to R_Ross=89 pm 5 R_sun, and together with the bolometric flux to T_eff=3795 K pm 70 K.Our approach illustrates the power of combining interferometry and high-resolution spectroscopy to constrain and calibrate stellar model atmospheres. The simultaneous agreement of the model atmosphere with our interferometric and spectroscopic data increases confidence in the reliability of the modelling of this star, while discrepancies at the detailed level of the high resolution spectra can be used to further improve the underlying model.

arXiv comment11 pages, 5 figures, accepted by A&A. Also available from http://www.aanda.org/articles/aa/pdf/forth/aa6032_06.pdf

References in corpus (15)

• Evolutionary tracks and isochrones for low- and intermediate-mass stars: from 0.15 to 7 M_sun, and from Z=0.0004 to 0.03
• The NextGen Model Atmosphere grid: II. Spherically symmetric model atmospheres for giant stars with effective temperatures between 3000 and 6800~K
• Local kinematics of K and M giants from Coravel/Hipparcos/Tycho-2 data. Revisiting the concept of superclusters
• TiO and H${}_2$O absorption lines in cool stellar atmospheres
• Interferometric observations of the supergiant stars alpha Orionis and alpha Herculis with FLUOR at IOTA
• Broad-band photometric colors and effective temperature calibrations for late-type giants. I. Z=0.02
• Tests of stellar model atmospheres by optical interferometry: VLTI/VINCI limb-darkening measurements of the M4 giant psi phe
• Data reduction methods for single-mode optical interferometry - Application to the VLTI two-telescopes beam combiner VINCI
• On the Limb Darkening, Spectral Energy Distribution, and Temperature Structure of Procyon
• Interferometric observations of the Mira star o Ceti with the VLTI/VINCI instrument in the near-infrared
• The interferometric diameter and internal structure of Sirius A
• ISO-SWS calibration and the accurate modelling of cool-star atmospheres - IV. G9 to M2 stars
• Direct multi-wavelength limb-darkening measurements of three late-type giants with the Navy Prototype Optical Interferometer
• The K-band intensity profile of R Leonis probed by VLTI/VINCI
• Tests of stellar model atmospheres by optical interferometry III: NPOI and VINCI interferometry of the M0 giant gamma Sge covering 0.5 - 2.2 microns

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