By Space Telescope Science Institute
March 22, 2022
How can we detect worlds around other stars? Planets are small and really faint compared to the stars they orbit. To conquer this difficulty, scientists use a variety of strategies to discover and define them.
For more details on the different techniques used to detect exoplanets, see How To Find an Exoplanet.
How do we find exoplanets?
Given that planets are close to much brighter stars, how do we actually find them?
Some planets are found by a technique that utilizes Einsteins theory of general relativity, observing the flexing effect of gravity from a concealed world as it deforms the light around its host star.
The most typical method is to try to find an eclipse or transit as a world passes in front of its host star. This is how the Kepler observatory found worlds, by gazing at a big region of the sky and waiting on worlds to pass in front of their stars, taking snapshots every second.
The Transiting Exoplanet Survey Satellite utilizes the very same technique on our nearby neighbor stars.
When a hidden planets gravity tugs on its host star, another technique observes very little changes in the stars position in the sky– the wobble that happens.
If the planet and star are oriented so that the star is moving toward or far from us, rather of side to side, we can spot the world as a shift in the stars light.
As far as getting photos of the actual exoplanets themselves, its possible, but very hard. The telescope has to obstruct the brilliant stars light to expose the faint world nearby.
How can we discover planets around other stars? Worlds are little and really faint compared to the stars they orbit. To conquer this challenge, researchers utilize a range of methods to find and define them.