Undergraduate Stellar Spectroscopy

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Session 88 -- Teaching Astronomy
Display presentation, Friday, January 14, 9:30-6:45, Salons I/II Room (Crystal Gateway)

[88.03] Undergraduate Stellar Spectroscopy

R.O. Gray, R.B. Dunning, C.E. Parker and D.A. Randell (Appalachian State University)

A classification-dispersion spectrograph constructed using off-the-shelf optical components has recently been commissioned at Appalachian State University's Dark Sky Observatory. Using an ST-6 CCD camera as the detector, undergraduate students in our senior seminar have used this spectrograph on our 18" cassegrain telescope to obtain high S$/$N (S$/$N>300) 3.3 $\AA$ resolution spectra in the H$\alpha$ region of a number of B - G type stars in the Bright Star Catalogue. These spectra have been used for a number of exercises. Much of the preliminary reduction of the spectra is done on MIRA, a PC-based image-processing program. The students obtain a wavelength calibration using a neon comparison spectrum, and then, using a spectrum of Vega, place the spectra on a relative flux scale, and use the slope of the continuum to estimate the temperature. With this estimate of the temperature, the PC-based spectral synthesis program SPECTRUM (Gray, 1991) is used to synthesize a number of synthetic spectra, based on Kurucz atmosphere models. By matching the synthetic spectra to the observed spectra, the students are able to obtain much better estimates of the effective temperature and gravity of their stars. Finally, the students measure the radial velocity of the stars, and apply a heliocentric correction.

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