Planetary system · 2 known planets · Centaurus

Proxima Centauri

Its star: not above the horizon after darkNever rises from London

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Where is Proxima Centauri?

Times for LondonChange city

Below the horizon from London all the time in Centaurus.

Rises: Never
Highest: —
Sets: —
Best after dark: —

Can I see Proxima Centauri?

No. The planets of Proxima Centauri can’t be seen with the eye, binoculars or any amateur telescope: they are lost in their star’s light. What you can do is point toward the star.

The star Proxima Centauri never rises from London: it is too far south in the sky for this latitude.

Why is Proxima Centauri interesting?

Proxima Centauri has 2 known planets, discovered between 2016 and 2020 by the radial velocity method.

All of them are close to Earth’s size or mass, based on the catalog values.

At about 4.2 light-years, it is one of the closest planetary systems to the Sun.

What can you see?

Eyes

Direction only

Not visible. Proxima is around magnitude 11.

Binoculars

Not visible in typical binoculars.

Telescope

A small telescope and a detailed chart show it as a faint reddish star. The planets themselves can’t be seen with any backyard telescope.

What you’re likely to see, not what a space telescope photographs.

About

Proxima Centauri is the nearest star to the Sun, about 4.2 light-years away. It is a small red dwarf and a distant companion of the bright pair Alpha Centauri A and B.

In 2016 astronomers announced Proxima b, a planet at least as massive as Earth that orbits in its star’s habitable zone every 11 days. A second, smaller planet, Proxima d, has since been confirmed closer in.

Whether Proxima b could support life is uncertain. Its star is prone to powerful flares that could strip away an atmosphere.

Even though it is the nearest star, Proxima is far too faint to see without a telescope.

Proxima has only about an eighth of the Sun’s mass. It is a flare star that can brighten suddenly for minutes at a time, and it takes several hundred thousand years to orbit Alpha Centauri A and B.

The Proxima Centauri system

Known planets of Proxima Centauri (catalog values from exoplanet.eu)
Planet	Mass	Radius	Orbit	From star	Found	Method
Proxima Centauri d	0.25 M⊕	—	5.17 days	0.0289 AU	2020	Radial Velocity
Proxima Centauri b	1.08 M⊕	—	11.2 days	0.0486 AU	2016	Radial Velocity

M⊕ / R⊕ = Earth masses / radii; M♃ / R♃ = Jupiter. Masses from radial velocity are often minimum masses. Data: The Extrasolar Planets Encyclopaedia, exoplanet.eu (CC BY 4.0).

Questions

Can I see Proxima b?

No. It is far too faint and close to its star. It was found from the tiny wobble it causes in the star’s motion.

Is Proxima Centauri the closest star?

Yes, apart from the Sun. It is about 4.2 light-years away.

Could we ever visit Proxima b?

Not with current technology. Our fastest spacecraft would take thousands of years to get there.

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Sources: The Extrasolar Planets Encyclopaedia (CC BY 4.0); star chart: Wikidata (CC0). Positions computed for your place and time with astronomy-engine. Data & Licences