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Date: 4 Apr 93 01:27:00 EST From: "STARS::HRSSHORE" <HRSSHORE%STARS.decnet@hrs.gsfc.nasa.gov> Subject: We interrupt this supernova for news about N Cyg 1992: New HST results Second GHRS Observation of Nova Cyg 1992, 1993 Apr. 1 -- Hot Off the Satellite Steve Shore (GHRS Science Team/CSC/GSFC), Sumner Starrfield (ASU), George Sonneborn (LASP/GSFC), Tom Ake (GHRS/CSC/GSFC), and Charo Gonzalez-Riestra (IUE/Vilspa) We have obtained a second Goddard High Resolution Spectrograph (GHRS) observation of Nova Cyg 1992 on 1 Apr. 1993. The data are all medium resolution (R=15000) large aperture 20 minute integrations. We have observed the following lines: N V 1240, O IV]/S IV] 1400, N IV] 1486, C IV 1550, [Ne V] 1575, [Ne IV] 1602, He II 1640, O III] 1665, N III] 1750, C III] 1910. The preliminary results show that the emission line profiles are now all optically thin. In our earlier observations on 1992 Sept. 7 we found that the resonance lines were all still optically thick. The [Ne IV], [Ne V], He II, and N IV] profiles are essentially identical, showing strong (50% or greater) contrast between the emission knots and the diffuse emission. The line widths are also the same, FWHM of about 2000 km/s (the wings are slightly narrower than seen in the earlier spectra). The C IV and N V profiles are quite similar, also displaying many knots of emission (much like those seem on Mg II 2800 since about 1992 May 20). An important result of this new observation is the confirmation that Lyman alpha was in emission in Sept. while it is now absent from the spectrum -- this supports its identification in the low resolution IUE data. The ejecta appear now to be spectroscopically dominated by a relatively small number of strong emission filaments, moving a comparatively low velocity (about 1000 km/s). We are continuing monitoring with IUE. Any observers who are able to obtain groundbased spectrophotometry are urged to communicate their results to this mail system, or directly to Steve Shore (hrsshore@stars.gsfc.nasa.gov) or Sumner Starrfield (starrfie@hydro.la.asu.edu). We are especially interested in He II 4686 and [O II] and [O III] profiles at comparable resolution to the GHRS spectra.
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