Limb Darkening: Getting Warmer

  • J. P. Aufdenberg
  • H.-G. Ludwig
  • P. Kervella
  • A. Mérand
  • S. T. Ridgway
  • V. Coudé du Foresto
  • T. A. ten Brummelaar
  • D. H. Berger
  • J. Sturmann
  • N. H. Turner
Part of the Eso Astrophysics Symposia book series (ESO)


We present interferometric observations and model atmosphere analyses of three stars: the F-type subgiant Procyon, the A-type supergiant Deneb, and the B-type supergiant Rigel. We use VLTI/VINCI and Mark III observations of Procyon to test recent multiwavelength limb-darkening predictions from 3-D hydrodynamic atmosphere simulations with no free parameters for convection. We also investigate the effects of different 1-D atmospheric convection treatments on limb-darkening predictions. We show that the 3-D model predictions are confirmed and we find that 1-D models fail to reproduce Procyon’s UV spectral energy distribution, a result consistent with models of granulation for Procyon’s surface. We use observations employing the longest baselines of the CHARA Array together with the FLUOR beam combiner to determine precise angular diameters for the two early-type supergiants and test limb-darkening predictions from expanding atmosphere models of these tars’ stellar winds. For Deneb, we derive angular diameters consistent with previous measurements, but which vary with position angle at the ≃3% level. Observations of the 2nd lobe of Deneb’s visibility curve are more consistent with expanding atmosphere predictions than hydrostatic atmosphere predictions. For Rigel, we derive from the CHARA/FLUOR observations a limb-darkened angular diameter consistent with a recent VLTI/IONIC measurement and 8% larger than reported from the Intensity Interferometer.


Position Angle Spectral Energy Distribution Solar Limb Angular Diameter Beam Combiner 
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Copyright information

© Springer 2007

Authors and Affiliations

  • J. P. Aufdenberg
    • 1
  • H.-G. Ludwig
    • 2
  • P. Kervella
    • 3
  • A. Mérand
    • 3
  • S. T. Ridgway
    • 1
    • 3
  • V. Coudé du Foresto
    • 3
  • T. A. ten Brummelaar
    • 4
  • D. H. Berger
    • 4
  • J. Sturmann
    • 4
  • N. H. Turner
    • 4
  1. 1.National Optical Astronomy Observatory950 N. Cherry Ave TucsonUSA
  2. 2.Lund ObservatoryLund University22100 LundSweden
  3. 3.Observatorie de Paris-MeudonLESIA, UMR 810992195 Meudon CedexFrance
  4. 4.Mt. Wilson ObservatoryThe CHARA ArrayMt. Wilson, CA 91023USA

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