AAVSO: American Association of Variable Star Observers

The Photometric and Spectroscopic Development of the 2019 Eruption of the Recurrent Nova V3890 Sgr Followed with Small Telescopes (Abstract)

Volume 48 number 2 (2020)

Forrest Sims


(Abstract only) V3890 Sgr is one of four known symbiotic-like recurrent novae (Red Giant donor and White Dwarf gainer). Detection of the most recent eruption was reported on August 27th, 2019, by A. Pereira at a visual magnitude of 6.7. In less than 21 days V3890 Sgr dropped to magnitude 12; after another 40 days it had reached near magnitude 16. Previous outbursts occurred in 1990 and 1962. We present the development of this outburst from photometric and spectroscopy measurements obtained with amateur equipment. Shortly after discovery, the visible spectrum at low resolution (R ~ 500) showed only weak emission features for Hα and Hβ, but with FWZI indicating Hα velocities in excess of 8,000 km/sec. Increases in the strengths and changes in the line profiles were recorded on a near daily basis. V-filter data derived from AAVSO observations were used to flux calibrate spectra. We highlight how the spectral changes reveal the passage of the ejecta through the wind of the companion red giant through its shock dynamics and radiative precursor and ionization front.