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D.K. Lynch (The Aerospace Corp.), J.C. Wilson (Cornell), N.A. Miller (NASA GSFC), R.J. Rudy, C.C. Venturini, S. Mazuk (The Aerospace Corp.), R.C. Puetter (UCSD)
We report the analysis of 0.8 - 2.5 µm spectrophotometry of CI Aquilae’s most recent outburst using the Cornell Massachusetts Slit Spectrograph (CorMASS) on the Palomar 1.5 m telescope and the Aerospace Near Infrared Imaging Spectrograph (NIRIS) on the Lick 3-m telescope. Spectra were obtained at thirteen epochs between May 2000 and June 2001, corresponding to approximately 3 and 391 days after peak brightness. The spectra begin as low-excitation, emission spectra showing primarily lines of H I and He I. In the earliest spectra He I 1.0830 µm and H I Br gamma 2.1655 µm appear to show P-Cygni profiles. The Lyman b-fluoresced O I lines at 0.8446 and 1.1364 µm are prominent in May 2000 but have all but vanished by June 2001. The line widths are about 4000 km/sec and many show evidence of doubled velocity structure. As the novae fades, the lines weaken relative to the continuum during the summer of 2000 and higher excitation lines begin to appear. By Sept 2000, coronal lines are evident and begin to dominate the spectrum: [Ca VIII] 2.3205 µm and possibly [Si VI] and [Si VII] at 1.9641 and 2.4807 µm, respectively. The slope of the continuum is low (Fl ~ l-2.4) and does not vary throughout the observation period. There is no evidence of dust formation or thermal emission from dust.
CI Aql is a "moderately fast" recurrent novae in an eclipsing binary system and is a member of the U Sco subclass novae. U Sco stars have slightly evolved secondaries and, in general, their shells do not appear to be significantly enriched in heavy elements. This suggests that little if any material from the white dwarf (WD) is being ejected and therefore it is likely that the WD is gaining mass from the accretion disk in the long run.
The authors acknowledge the assistance of The Aerospace Corporation’s Independent Research and Development program, and the US Air Force Space and Missile Systems Center through the Mission Oriented Investigation and Experimentation program, under contract F4701-00-C-0009. We would like to thank T. Armstrong and W. Earthman for assistance at the telescope.
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Bulletin of the American Astronomical Society, 34
© 2002. The American Astronomical Soceity.