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J.E. Lyke, J. Song (U. of Minn.), R.M. Wagner (LBTO), K.M. Vanlandingham (Bio2 Center), C.G. Mason (SETI Institute), C.E. Woodward (U. of Minn), R.D. Gehrz (U. of Minn.), S.G. Starrfield (ASU)
We present 1-20 micron observations of classical Nova Aquilae 1999 No. 2 (V1494 Aql) that cover the first 10 days after discovery plus additional near-IR photometry on 3 February 2000 with the 1.54-m Mt. Lemmon Observing Facility and the 0.76-m O'Brien Observatory and optical spectra obtained on 2000 April 25 and June 4 with the MDMO 2.4-m Hiltner telescope and CCDS covering the interval 3200-6800 Åat a spectral resolution of about 9 Å.
Our early spectral energy distributions (SEDs) deviate from the typical classical nova SED soon after outburst. They can be fit by a two-component blackbody model and one possible interpretation of this fit is that the hotter component is the expanding fireball while the cooler component is an existing shell of circumstellar material or a fast precursory shell.
The spectra exhibit strong and broad permitted emission lines arising from the Balmer series of hydrogen, He I, He II, C III, NIII, and Fe II. Intense forbidden emission lines of [O III] 5007, 4959, and 4363 Å; [N II] 5755 Å; and [Fe VII] 6085 Åare also present. The line profiles are rectangular but exhibit a striking castellated structure indicating that the ejecta consist of many large, dense condensations. The mean expansion velocity inferred from the line profiles is ~q 2500 km/s.