A planetary-mass object, PMO, or planemo is a celestial object with a mass that falls within the range of the definition of a planet: massive enough to achieve hydrostatic equilibrium (to be rounded under its own gravity), but not enough to sustain core fusion like a star. By definition, all planets are planetary-mass objects, but the purpose of the term is to describe objects which do not conform to typical expectations for a planet. These include dwarf planets, the larger moons, free-floating planets not orbiting a star, such as rogue planets ejected from their system, and objects that formed through cloud-collapse rather than accretion (sometimes called sub-brown dwarfs).
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Famous quotes containing the word objects:
“Luckless is the country in which the symbols of procreation are the objects of shame, while the agents of destruction are honored! And yet you call that member your pudendum, or shameful part, as if there were anything more glorious than creating life, or anything more atrocious than taking it away.”
—Savinien Cyrano De Bergerac (16191655)