Also found in: Thesaurus, Medical, Encyclopedia.


The point at which an object is farthest away from the center of mass of the star it is orbiting.

[ap(o)- + Greek astron, star (probably on the model of aphelion); see ster- in Indo-European roots.]
American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
References in periodicals archive ?
After the simulation has completed one orbit, the screen displays the precession per orbit and an integer that counts the passages through apastron (maximum separation).
Red lines connect the central body to the apastron points.
Adding a test to the program, I had it print the coordinates of Jack each time it reached its far point from the sun, called apastron. The results are plotted in the lower diagram on page 79.