An Etymological Dictionary of Astronomy and Astrophysics

1. A → binary star system in which the two → components are so close that they exchange gases in a complex manner. Their overlapping → gravitational fields form a “peanut” shaped → equipotential surface.
   

2. Two roughly similar-sized asteroids or cometary nuclei resting on one another, presumably after coming together very gently. Examples are → Comet 67P/Churyumov-Gerasimenko and the asteroid → (486958) 2014 MU69.

See also: → contact; → binary.