periastron

American  

[per-ee-as-truhn, -tron] / ˌpɛr iˈæs trən, -trɒn /

noun

Astronomy.

plural

periastra

1. the point at which the stars of a binary system are closest (apastron ).

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periastron British  

/ ˌpɛrɪˈæstrɒn /

noun

1. astronomy the point in the orbit of a body around a star when it is nearest to the star, esp applied to double-star systems

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periastron Scientific  

/ pĕr′ē-ăs′trən,-trŏn /

plural

periastra

1. The point at which an object, such as a planet or comet, is closest to the center of mass of the star it is orbiting.

2. Compare apastron

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Other Word Forms

• periastral adjective

Etymology

Origin of periastron

1850–55; < peri- + Greek ástron star; modeled on perihelion

Example Sentences

These orbs complete a revolution in 180 years, and when in apastron are seventeen times more remote from each other than when at periastron.

From Project Gutenberg

The pair travel in an orbit from fourteen to forty-two times the radius of the Earth’s orbit; so that when at apastron they are three times as distant from each other as when at periastron.

From Project Gutenberg

The eccentricity of their orbit approaches in form that of Faye’s comet, which travels round the Sun; consequently the stars, when at apastron, are twice their periastron distance.

From Project Gutenberg

All went well, there were no incidents, no vessels disturbed him; though had the two components of the binary been at periastron, it would have simplified the work with the position micrometer.

From Project Gutenberg

The last periastron was ninety years ago, and we've only been here for sixty-odd; all we have is verbal accounts from memory from the natives, probably garbled and exaggerated.

From Project Gutenberg