Spirographic Orbit of a Star in Extended Mass Distribution

ϵ

0.9

q

max

0.4

t

40

This Demonstration shows the orbit of a point mass through a Hernquist potential, which represents a star moving through a spherically symmetric extended mass distribution with a density profile of the form

ρ=

ρ

0



3

z(1+z)

, where

z=r/

r

s

is the dimensionless radius and

r

s

is the length scale of the potential. This type of mass density has been used to model physical systems such as dark matter halos, elliptical galaxies, and embedded young star clusters.