Tabetha S. Boyajian, Harold A. McAlister, Gerard van Belle, Douglas R. Gies, Theo A. ten Brummelaar, Kaspar von Braun, Chris Farrington, P. J. Goldfinger, David O'Brien, J. Robert Parks, Noel D. Richardson, Stephen Ridgway, Gail Schaefer, Laszlo Sturmann, Judit Sturmann, Yamina Touhami, Nils H. Turner, Russel White
We have executed a survey of nearby, main sequence A, F, and G-type stars
with the CHARA Array, successfully measuring the angular diameters of fortyfour
stars with an average precision of ~ 1.5%. We present new measures of the
bolometric flux, which in turn leads to an empirical determination of the
effective temperature for the stars observed. In addition, these
CHARA-determined temperatures, radii, and luminosities are fit to Yonsei-Yale
model isochrones to constrain the masses and ages of the stars. These results
are compared to indirect estimates of these quantities obtained by collecting
photometry of the stars and applying them to model atmospheres and evolutionary
isochrones. We find that for most cases, the models overestimate the effective
temperature by ~ 1.5-4%, when compared to our directly measured values. The
overestimated temperatures and underestimated radii in these works appear to
cause an additional offset in the star's surface gravity measurements, which
consequently yield higher masses and younger ages, in particular for stars with
masses greater than ~1.3 Msun. Additionally, we compare our measurements to a
large sample of eclipsing binary stars, and excellent agreement is seen within
both data sets. Finally, we present temperature relations with respect to (B-V)
and (V-K) color as well as spectral type showing that calibration of effective
temperatures with errors ~ 1% is now possible from interferometric angular
diameters of stars.
View original:
http://arxiv.org/abs/1112.3316
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