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Session 68 - Degenerate Stars, Pulsars.
Display session, Thursday, June 11
The STIS spectrograph on HST was used to obtain a spectrum of the white dwarf star Procyon B. Procyon B is a challenging object because it is a close binary companion of the 1st magnitude star Procyon A. In the spring of 1998, Procyon B was near apastron (approximately 5 arc sec from Procyon A) and we succeeded in obtaining a clean spectrum of it, with the sky background averaging a few percent of the stellar signal.
The spectrum clearly shows that Procyon B is a DZ white dwarf star, with a temperature near the values previously determined from HST photometry. Identifying features in the spectrum as being real is a sensitive issue. With our high S/N (>100), even the faint sky background can produce artifacts in the stellar spectrum. At this time we can claim the Mg II h and k lines and a number of Fe II features as being definitely real.
This work has been supported by the HST Guest Observer Program (GO-07398.01-96A).
Program listing for Thursday