The Last Measurements Made with the Wampler Scanner. II. Tests of Temperature Determinations from Flux Data for FGK IV-V Stars

Abstract

ABSTRACTNew flux data are presented for 60 FGK stars on and near the main sequence. All the measurements are made at wavelengths suitable for temperature determinations. Measurements of all but seven program stars include four passbands in the Brackett continuum as well as 12 passbands in the Paschen continuum. After the accuracy of the new data is shown to be satisfactory, measurements of three “solar proxies” are compared to theoretical flux data from a solar model atmosphere calculated by Kurucz. In this case, agreement with rms scatter at the 5–7 mmag level is obtained. In addition, a possible zero-point problem with synthetic photometry of two Kurucz solar atmospheres is detected. Using measurements for 48 of the program stars and the Kurucz model grid, two sets of temperature data are then derived. The first set is based solely on data for the Paschen continuum, and the second set is derived from data for both the Paschen and Brackett continua. When the resulting temperatures are compared to temperature data on an angular-diameter scale, some data in the first data set yield offsets of about 40 K. However, no such offsets are found for the second data set. It is concluded that the Kurucz models yield correct continua between 6056 and 10404 Å for the program stars. In contrast, it appears that some of those models do not quite reproduce the line blocking in that wavelength range. The latter deduction is supported by analyzing flux data for a star (61 Cyg A) with relatively large amounts of line blocking. It is recommended that the measurements reported here be used again when further tests of theoretical flux curves for FGK stars are performed.