Abstract:
Near-infrared spectra of the very fast ReiN-type nova, Nova
Sagittarii 2001 (V464a Sgr) obtained in the early decline phase and the period
110 to 170 days after the discovery date are presented. The spectrum in the
early decline phase is dominated by emission lines of hydrogen and accompanied
by fluorescence excited 0 I line at 1.129 I'm. These lines have broad symmetric
emission wings with full width at zero intensity (FWZI) corresponding to a
velocity of "". 10,000 km S-I. About 120 days after the discovery the K band
spectrum is dominated by emission lines due to Si VI and Si VII at 1.963 I'm
and 2.476 JIm indicating that the nova had entered .the coronal phase. The
line ratios of Brackett series deviate substantially from case B values indicating
optical depth effects.
