Measuring stellar temperatures : an astrophysical laboratory for undergraduate students

While astrophysics is a fascinating subject, it hardly lends itself to laboratory experiences accessible to undergraduate students. In this paper we describe is presented a feasible astrophysical laboratory experience, in which students are guided to take several stellar spectra, using a telescope, a spectrograph and a CCD camera, and perform a full data analysis using the equivalent widths method on some spectral lines. This allows them to derive stellar temperatures after a suitable calibration and fitting procedure. On average the estimated stars temperatures agree with known results within an error margin of 5 to 10% for cold stars, and 20 to 25% for hot stars.