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).
|Number of pages||6|
|Journal||The Astrophysical Journal Letters|
|Publication status||Published - 1 Dec 2012|