perihelion

American  

[per-uh-hee-lee-uhn, -heel-yuhn] / ˌpɛr əˈhi li ən, -ˈhil yən /

noun

Astronomy.

plural

perihelia

1. the point in the orbit of a planet or comet at which it is nearest to the sun.

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perihelion British  

/ ˌpɛrɪˈhiːlɪən /

noun

1. the point in its orbit when a planet or comet is nearest the sun Compare aphelion

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perihelion Scientific  

/ pĕr′ə-hē′lē-ən /

1. The point at which an orbiting object, such as a planet or a comet, is closest to the Sun.

2. Compare aphelion perigee

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Other Word Forms

• perihelial adjective
• perihelian adjective

Etymology

Origin of perihelion

1660–70; < Greek peri- peri- + hḗli ( os ) sun + -on neuter noun suffix, on the model of perigee; earlier in the New Latin form perihelium

Compare meaning

How does perihelion compare to similar and commonly confused words? Explore the most common comparisons:

• aphelion vs. perihelion

Example Sentences

Dr Balaji said opportunities to spot the comet may occur "in the days around perihelion, depending on local conditions and the comet's behaviour".

From BBC • Jan. 13, 2025

The mission is approaching its 19th perihelion on March 30, 2024 at a distance of 11.5 solar radii from Sun center.

From Science Daily • Mar. 27, 2024

The most surprising thing about this cycle, though, is probably when its extremes occur on the calendar: perihelion is in January every year, while aphelion is in July.

From Scientific American • Jun. 30, 2023

Even as the Northern Hemisphere experiences winter’s chill, our planet on Wednesday will be at perihelion, the closest it gets to the sun during its elliptical orbit.

From New York Times • Jan. 1, 2023

Comets must lose much of their original substance every time they return to perihelion.

From Astronomy: The Science of the Heavenly Bodies by Todd, David Peck