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arXiv · 1211.6055

Resolving Vega and the inclination controversy with CHARA/MIRC

J. D. Monnier·Xiao Che·Ming Zhao·S. Ekstrom·V. Maestro·J. 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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Abstract

Optical and infrared interferometers definitively established that the photometric standard Vega (alpha Lyrae) is a rapidly rotating star viewed nearly pole-on. Recent independent spectroscopic analyses could not reconcile the inferred inclination angle with the observed line profiles, preferring a larger inclination. In order to resolve this controversy, we observed Vega using the six-beam Michigan Infrared Combiner on the Center for High Angular Resolution Astronomy Array. With our greater angular resolution and dense (u,v)-coverage, we find Vega is rotating less rapidly and with a smaller gravity darkening coefficient than previous interferometric results. Our models are compatible with low photospheric macroturbulence and also consistent with the possible rotational period of ~0.71 days recently reported based on magnetic field observations. Our updated evolutionary analysis explicitly incorporates rapid rotation, finding Vega to have a mass of 2.15+0.10_-0.15 Msun and an age 700-75+150 Myrs, substantially older than previous estimates with errors dominated by lingering metallicity uncertainties (Z=0.006+0.003-0.002).

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J. D. Monnier, Xiao Che, Ming Zhao, S. Ekstrom, V. Maestro, J. 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. 2012-11-27. Resolving Vega and the inclination controversy with CHARA/MIRC. https://doi.org/10.1088/2041-8205%2F761%2F1%2Fl3

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