NEAR-INFRARED SPECTROSCOPY OF V1974-CYGNI-1992 - NEW CORONAL EMISSION-LINES IN CLASSICAL NOVAE

The near-infrared (1.2-2.4 mu m) spectrum of V1974 Cygni (Nova Cygni 1 992) was observed on 1993 May 2 at a spectral resolution of 570 using the Ohio State University Infrared Imager/Spectrometer on the Perkins 1.8 m telescope. In agreement with previous Infrared spectra of novae and V1974 Cyg in particular, we find emission lines of [Al IX], [Ca VI II], [Si VI], and [S IX] present in our spectra. However, contemporane ously with the appearance of enhanced soft X-ray emission observed by ROSAT in early 1993,we report the discovery of infrared coronal lines arising from ions not previously observed in classical novae. These in clude [P VIII] 1.737 mu m, [P VII] 1.377 mu m, [Si X] 1.430 mu m, [S X I] 1.395 mu m, [Ti VI] 1.715 mu m, and possibly [Cr XI] 1.550 mu m and [Ti X] 1.332 mu m. Optical spectroscopy confirms the high degree of i onization and gives T-e similar or equal to 20,000 K in the [Fe VII] r egion. Photoionization from the hot white dwarf remnant can account fo r the high degree of ionization and relatively low excitation temperat ure of the ejecta. Our discovery of phosphorus in the ejecta when comb ined with the results of recent hydrodynamic studies of accretion onto white dwarfs suggests that the white dwarf in V1974 Cyg 1992 must be extremely massive.