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G.J. Schwarz (West Chester University), C.E. Woodward (University of Minnesota), D.K. Lynch, R. Rudy (The Aerospace Corp.), G. Ruch, A. Helton (University of Minnesota), C.C. Venturini (The Aerospace Corp.), J.E. Lyke (Keck Observatory), M.F. Bode (Liverpool John Moores Univ.), Spitzer CY1 GO ToO Nova Team
The first classical nova observed in our Spitzer Cycle 1 ToO program (PID 2333) was V1186 Sco. This slow nova exhibited a light curve with multiple secondary peaks similar to PW Vul. Visual maximum occurred on 9 July 2004 while the time to decline 2 magnitudes, t2, was ~25 days. However, the erratic nature of the light curve makes any determination of intrinsic properties based on the decline times (e.g. luminosity) problematic. Spitzer 5-37 micron spectra were obtained of V1186 Sco and V1187 Sco in late September 2004 and March 2005. V1187 Sco was a very fast nova that was discovered only a few days after V1186 Sco. The first spectra of V1187 Sco showed strong forbidden lines, primarily of neon and magnesium, superimposed on a weak hydrogen recombination spectrum (Lynch et al. 2005, ApJ in press). Both the early and late evolutionary epoch spectra of V1186 Sco were dominated by hydrogen lines. Not unexpected due to its extreme decline time and likely ONeMg white dwarf progenitor, V1187 Sco was dominated by very high ionization "coronal" lines of [Mg V], [Mg VII], [Ar V], [Ne V], and [Ne VI] when Spitzer observations resumed in March 2005. Due to its much slower evolution, the Spitzer data of V1186 Sco obtained the same month showed a greatly weakened hydrogen recombination spectrum with a surprising emergence of the [Ne II] (12.8 micron) as the strongest line. It is not clear if the V1186 Sco outburst occurred on a an ONeMg white dwarf as our complementary ground based optical and near-IR spectroscopy obtained during this later epoch show none of the typical characteristics of an ONeMg nova. However, given the rather slow development of this object it might be too early to make any determination of the white dwarf progenitor.
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Bulletin of the American Astronomical Society, 37 #4
© 2005. The American Astronomical Soceity.