Stellar temeratures by Wien's law : not so simple

A star’s surface temperature is among the most important features that can be deduced from its light. We have made measurements to see how reliably we could determine the surface temperatures of some A to K stars using Wien’s Displacement Law. We took spectra, corrected them for atmospheric extinction and instrumental response, found the wavelengths of their intensity maxima, and then from Wien’s law found the surface temperatures of the observed stars. For F to early K stars, our results agree with temperatures determined in other ways. For A and later K stars, the agreement is poor because the spectra are appreciably different from ideal blackbody spectra and because our equipment responds poorly to the deep red and blue wavelengths where the spectra of these stars have their peak intensities. This paper points out several interesting concepts in and outside the astrophysical domain that can be instructive for undergraduate students.