What dictates the precise velocity tuning for a star located far from the galactic center?
Answer
The collective mass enclosed within its orbit
The velocity of a star at a specific radius within a galaxy is not random; it is precisely determined by the total gravitational pull exerted by all the mass situated closer to the core, meaning the mass enclosed within that star's orbit. This relationship ensures a delicate equilibrium. If the star moves too fast relative to this enclosed mass, it escapes; if it moves too slowly, it spirals inward. This characteristic speed is derived directly from the integrated mass distribution inside that particular orbit, equating the motion to planetary motion scaled up vastly.
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