RR Pictoris is a cataclysmic variable star system that flared up as a nova that lit up in the constellation Pictor in 1925. It was first noticed by South African astronomer R. Watson on 25 May 1925 when it had an apparent magnitude of 2.3. It continued to brighten to magnitude 1.2, which it reached on 9 June 1925. It dimmed to magnitude 4 by 4 July, but brightened again to 1.9 on 9 August.
The brightness of RR Pictoris decreased in 150 days by 3 mag. Today RR Pictoris has a brightness of 9 mag.
Novae are close binary systems composed of a white dwarf and secondary star that is so close it is filling up its Roche lobe with stellar material, which is then transferred onto the first star's accretion disc. Once this material reaches a critical mass, it ignites and the system brightens tremendously. The two stars of RR Pictoris orbit each other every 3.48 hours. Calculations of the speed suggest the secondary star is not dense enough for its size to still be on the main sequence, so it itself must have begun expanding and cooling already as its core has run out of hydrogen fuel.