The last measurements made with the Wampler scanner. I. An analysis of the consistency and accuracy of flux curves for bright standard stars.
Abstract (from CDS):
From 1980 through 1998, the Wampler scanner and the 0.9 m Crossley reflector at Lick Observatory were used to obtain 137 nights of flux-curve measurements. In this paper, the resulting data are used to test, revise, and extend a set of flux curves for bright standard stars published in 1984. Full use is made of extensive measurements of α Lyr, the primary standard star. It is found that measurements made during spring and fall runs are highly consistent and that small systematic wavelength trends appearing in the standard-star data can be readily detected and corrected. This conclusion applies for 109 Vir in particular, and it is concluded that there is no convincing case for variation of this key standard star after 1979. Tests of the corrected and augmented flux curves using 13 color photometry yield a number of cases in which residuals are systematic with wavelength. However, for stars with E(B-V)<0.12 mag (including α Lyr), the revised and extended flux-curve data yield synthetic values of Strömgren u-b and b-y that are highly consistent with results from filter photometry. For almost all stars measured (again including α Lyr), consistency with filter values of (V-R)C is also obtained. Comparisons of the revised and augmented data with flux curves measured in the Soviet Union yield results ranging from fair agreement to marked disagreement. However, it is found that published data from additional sources include results that agree well with those presented here. Given this agreement, the results of the tests using filter photometry, and the character of the transformation coefficients for α Lyr, it is concluded that there is adequate support for the accuracy of the corrected standard-star flux curves. Recommendations about future measurements that can be used to test this conclusion are presented.
stars: fundamental parameters (colors)