Resolving Vega and the inclination controversy with CHARA/MIRC

J. D. Monnier, Xiao Che, Ming Zhao, S. Ekström, V. Maestro, Jason Aufdenberg, F. Baron, C. Georgy, S. Kraus, H. McAlister, E. Pedretti, S. Ridgway, J. Sturmann, L. Sturmann, T. ten Brummelaar, N. Thureau, N. Turner, P. G. Tuthill

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88 Citations (Scopus)


Optical and infrared interferometers definitively established that thephotometric standard Vega (=¿ Lyrae) is a rapidly rotating starviewed nearly pole-on. Recent independent spectroscopic analyses couldnot reconcile the inferred inclination angle with the observed lineprofiles, preferring a larger inclination. In order to resolve thiscontroversy, we observed Vega using the six-beam Michigan Infrared Combiner on the Center for High Angular Resolution Astronomy Array. Withour greater angular resolution and dense (u, v)-coverage, we find thatVega is rotating less rapidly and with a smaller gravity darkeningcoefficient than previous interferometric results. Our models arecompatible with low photospheric macroturbulence and are also consistentwith the possible rotational period of ~0.71 days recently reportedbased on magnetic field observations. Our updated evolutionary analysisexplicitly incorporates rapid rotation, finding Vega to have a mass of2.15+0.10 - 0.15 M &sun; and anage 700-75 + 150 Myr, substantially olderthan previous estimates with errors dominated by lingering metallicityuncertainties (Z = 0.006+0.003 - 0.002).
Original languageEnglish
Article numberL3
Number of pages6
JournalThe Astrophysical Journal Letters
Issue number1
Publication statusPublished - 1 Dec 2012


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