Spectroscopic observations of the recurrent symbiotic nova V407 CYG during 2001-2009

摘要

We analyze the results of our spectroscopic monitoring of V407 Cyg in 2001-2009. The slow decline in optical brightness connected with the evolution of a Z And-type outburst (maximum in 1998) was observed in 20012003. The system returned to quiescence in 2004, and its spectrum returned to nearly the same as in 1994. We estimated the hot component's temperature from the equivalent width of HeII 4686 ? to be ～ 63 000 K. During 2006-2007 there was no clear evidence of the hot component in the spectra. The equivalent width of Ha dropped to 5 ? (in 2007). This passive state was similar to previous passive states observed during 2006-2007 and in 1991.