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

After several Earth flybys and a carefully planned encounter with Jupiter, the spacecraft will settle into a 1.5-year orbit with a perihelion of about 1 AU and an inclination of up to 75°.

From Science Daily

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

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

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

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