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

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

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

From New York Times • Jan. 1, 2024

The last perihelion, if you’re wondering, was on January 4, 2023, and Earth’s center was 147,098,924 km from that of the sun, or about 1.5 percent closer than average.

From Scientific American • Jun. 30, 2023

If Newton's theory is absolutely true, the excess motion of Mercury's perihelion remains a mystery.

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