BB Doradus or BB Dor is a
cataclysmic variable
In astronomy, cataclysmic variable stars (CVs) are stars which irregularly increase in brightness by a large factor, then drop back down to a quiescent state. They were initially called novae (), since ones with an outburst brightness visible to ...
, a pre-nova star, thus a close pair binary star system. It is composed of a red dwarf and a white dwarf.
[ Observations of the white dwarf's faint but certain accretion disk are consistent with it being at ~10° inclination (to the line of sight from the Earth).][
Its parallax (movement against background stars due to the Earth's orbit around the Sun) given by the ''Gaia'' space observatory's second data release puts the pair at about 3,000 light years away.]
References
{{DEFAULTSORT:BB Doradus
Cataclysmic variable stars
Dorado
Doradus, BB
M-type main-sequence stars
White dwarfs