Recurring Nova RS Oph spectroscopic observation at Bosscha Observatory and ITERA Astronomical Observatory (IAO)

Abstract

We report low and intermediate resolution spectra of the recurrent nova RS Oph taken at two observatories. A low resolution spectrum (R ≈ 1000) was taken at ITERA Astronomical Observatory (IAO) in Lampung by using 25 cm (f/8) RC Astrograph telescope equipped with a LISA Pack Spectrograph eight days after the outburst. Twenty intermediate spectra (R ≈ 5000) were taken on several consecutive nights using LHIRES III spectrograph attached to a 25 cm (f/10) Meade LX-200R telescope at Bosscha Observatory, Lembang. We identified significant change in the strength of atomic lines from low resolution spectrum compared to previous observations. A clear and distinct Balmer emission decrement can be seen from the spectrum. Our intermediate resolution spectroscopy revealed a variability of P-Cygni profile on a broad Hα line. The P-Cygni profile evolved and disappeared at recent observations. It is thought that there was a new shell formed after the outburst and later combined with the previous shell in the next days. From the broad Hα profile, we measured and found decreasement in expansion velocity during our observation. We estimated vexp = 2907.97 ± 64.14 km/s and vexp = 997.12 ± 8.18 km/s on 1.6440 and 22.729 days after the outburst, respectively.