Methods of discovering exoplanets

In this article, we'll tell you about how exoplanet discoveries made. Actually, there are too much methods but in this article we'll tell about the most common ones.


This is is the most common method. 76% of exoplanets(3226) have been discovered by this way.

When a planet passes evenly between its star and observer, the stars light gets dimmed by planet by a measurable amount. Sometimes it might not be an exoplanet and it can mislead the experts so experts analyze the periods(how long it takes the planet to orbit once around the star) of dimming of the light Once exactly detected, the planet's orbital size can be calculated from the period and the mass of the star.

Radial Velocity

Orbiting planets might cause stars to wobble in space. The wobble method measures changes in a star’s “radial velocity.” The wavelengths of starlight are alternately squeezed and stretched as a star moves slightly closer, then slightly farther away from us. Those gyrations are caused by gravitational tugs, this way and that, from orbiting planets.

19% of exoplanets(822) have been discovered by this method. If experts couldn't use the transit method, this one is alternative.

Gravitational Microlensing

Only 9 planets have been discovered using this method so far. Well, what's that?

The gravity of a star in the foreground magnifies the light from a background star that passes just behind it. If the foreground star has a planet in orbit, the star appears to a properly positioned telescope as a spike in light intensity as the background star goes by; the planet appears as a second, smaller spike.


It is not an easy way to take an image of exoplanet. Astronomers use some techniques that remove the overwhelming glare of the stars they orbit. Only 1.2% of exoplanets have been discovered using this method.

For example HR 8799 system:

HR 8799 is a roughly 30 million-year-old main-sequencestar located 133.3 light-years (40.9 parsecs) away from Earth.

Here we can see 4 massive planets around the star.

For more information about HR 8799:

These are the most common methods to discover exoplanets around stars. There are more:

Transit Timing Variations, Eclipse Timing Variations, Pulsation Timing Variations etc. But these ways don't even cover more then 0.48% of exoplanets.

Thank you for reading.





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