They think it was part of a two-star or binary system.
If it actually is in the nebula, perhaps its one member of a former binary system, the other star being the one that exploded.
Both pulsars and bursters, astrophysicists have long thought, involve a binary system: two stars orbiting each other.
For one thing, the stars may have started life in a binary system, in a tight orbit around another star.
binary system technologies offer both environmental advantages and disadvantages.
British Dictionary definitions for binary system
binary notation
noun
1.
a number system having a base of two, numbers being expressed by sequences of the digits 0 and 1: used in computing, as 0 and 1 can be represented electrically as off and on