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

On Monday, the comet was at perihelion, the point at which it is closest to the Sun, which influences how bright it appears.

From BBC • Jan. 13, 2025

PSP uses a series of Venus flyby's to gradually reduce its perihelion from 36 solar radii in 2018 to 9.5 in 2025.

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

It appears that variations in the position of the earth at perihelion have a real though slight influence in causing cycles with a length of about 21,000 years.

From Climatic Changes Their Nature and Causes by Huntington, Ellsworth