IR Spectrophotometry of Novae Aquilae 1993 \& Ophiuchi 1993

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Session 55 -- Interacting Binaries: CVs and XRBs
Display presentation, Thursday, January 13, 9:30-6:45, Salons I/II Room (Crystal Gateway)

[55.02] IR Spectrophotometry of Novae Aquilae 1993 \& Ophiuchi 1993

C.E. Woodward, J. Cole (WIRO), R.D. Gehrz, G.F. Lawrence (U. Minnesota), M.A. Greenhouse (SI/NASM), D. Van Buren (Caltech), G. Sloan (GL)

The study of novae provides insight into an important chemical enrichment process in the interstellar medium. Infrared spectrophotometry of these transient events provides clues to the chemical composition of dust condensates which may form in the cooling ejecta, and the gas phase elemental abundances. As part of our continuing infrared survey of novae we present spectroscopic and photometric observations of two recent novae, Aquilae 1993 and Ophiuchi 1993, obtained during the first 250 days after discovery.

Analysis of our multiwavelength photometric data of N Aql93 indicates that dust condensation commenced near day 45, and reached maximum development (inferred from 3~$\mu$m broadband colors) on about day 80. Near-infrared spectroscopy obtained near the end of the free-free expansion phase of a pseudophotosphere, prior to the onset of dust formation, revealed emission lines of C, Fe, Mg and O. Strong Fe II multiplets also where present in the optical spectrum of the nova at this epoch (Austin \& Starrfield 1993, IAUC 5793), resulting in the classification of this object as a Fe~II nova. As of day 200, our mid-infrared data show no evidence of [Ne II] emission at 12.8~$\mu$m.

Spectroscopy of N Oph93 approximately 62 days after outburst revealed the presence of infrared coronal line emission from [Ca~VII] 2.322(2)-$\mu$m and [Si~VII] 2.470(2)-$\mu$m. Emission from hydrogen (Br$\gamma$ 2.169(1)-$\mu$m) and helium (He~I 2.060(2)-$\mu$m) also were present in the spectra. The lines were velocity resolved at $\approx$~3600 km/s FWHM.

The infrared evolution of both novae, inferred from these temporal data sets, will be discussed and compared to observations of other classical novae including V1974~Cygni. This work was supported in part by NSF grant AST91-16644 (Wyoming), NSF grants to Minnesota and the Graduate School of Minnesota.

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