How many exoplanets have been discovered?

NASA estimates that the Milky Way Galaxy is home to at least 100 billion planets. Others believe it could be anywhere from 200-300 billion. Using data from exoplanet-hunting missions such as Kepler, Gaia, and now James Webb, we can identify and confirm their existence. So, how many exoplanets have been discovered?

Number of confirmed exoplanets: 5,084

Number of confirmed planetary systems: 3,811

NASA exoplanet candidates (unconfirmed): 8,912
Updated Sept. 14, 2022

These are the number of confirmed exoplanets and planetary systems by NASA, followed by the number of exoplanet candidates, which are discoveries that could be planets but are still unconfirmed by researchers.

Exoplanet Illustration. Credits: NASA, ESA, CSA, and L. Hustak (STScI)

What is an exoplanet?

An exoplanet is any planet orbiting a star outside of our solar system. Exoplanets can come in many different sizes and compositions. NASA categorizes the 5,084 confirmed exoplanets into 5 subtypes: Neptune-like, Super Earth, Gas Giant, Terrestrial, and the unknowns. Here’s how the space agency describes each:

Neptune-like (1,777)
These planets are Neptunian worlds, similar to Uranus or Neptune in our solar system.

Super Earth (1,579)
Super Earths are exotic planets unlike any in our solar system–more massive than Earth yet lighter than gas giants like Neptune, and they can be made of gas, rock, or a combination of both.

Gas Giant (1,535)
These planets belong to a class known as gas giants, similar to Jupiter or Saturn in our solar system.

Terrestrial (188)
Terrestrial planets ae rocky, with iron-rich cores, like Mercury, Venus, Earth, and Mars in our solar system.

Unknown (5)

Credit: NASA/JPL-Caltech

How do we find them?

Currently, there are 5 different methods scientists use to identify exoplanets. These include measuring tiny changes in a star’s brightness to looking for wobbling stars, usually caused by orbiting planets. Here’s how many exoplanets have been discovered by each method:

Radial Velocity: 935 planets discovered
Watching for the wobble of a star.

Transit Method: 3,892 planets discovered
Measuring a star’s dip in brightness.

Direct Imaging: 61 planets discovered
Taking pictures.

Gravitational Microlensing: 135 planets discovered
Measuring light in a Gravity Lens.

Astrometry: 1 planet discovered
Measuring a star’s minuscule movements on a plane.

You can see more about each on NASA’s Exoplanet Exploration page.

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