Rise and fall of silicate dust in RS Ophiuchi following the 2006 eruption

ABSTRACT We present an analysis of archival Spitzer InfraRed Spectrograph (IRS) observations the recurrent nova RS Ophiuchi obtained on several occasions, beginning about 7 months after outburst in 2006. These data show atomic emission lines, absorption bands due to photospheric SiO, and well-known silicate dust features at 9.7 $18\, \mu$m. The emission, arising wind secondary star, is fitted by dusty models for mass-loss rates range 1.0–1.7 × 10−7 M⊙ yr−1. are similar profile those seen circumstellar environments isolated late-type stars some symbiotic binaries, although longer wavelength feature peaks $17\, \mu$m, instead usual indicating peculiar grain properties. variable, appearing stronger 2006–2007 during than 2008–2009 when system was quiescent state. This variability attributed changes ultraviolet output reformation accretion disc, a decline rate red giant star could also play role. Further observations, aftermath 2021 eruption, provide definitive conclusion.