An extrasolar planet, or “exoplanet”, is any planet that orbits a star other than the Sun. We know of exoplanets of all sizes, from bigger than Jupiter to smaller than Earth. Just like in our Solar System, exoplanets can orbit their stars at any distance; some exoplanets orbit so close to their stars that their surface temperatures are hot enough to melt iron! Some exoplanets will orbit at just the right distance that we say they’re in their star’s “habitable zone”, that they are the right temperature to have liquid water at their surface and might be able to support life.
Exoplanets are difficult to see directly from Earth. Because they are so small and faint, they are easily lost in the glare of the bright stars they orbit, so we often use indirect methods to find them. One of these is called the “transit method”, where we carefully measure the brightness of a star over a long period of time, and look for periodic decreases in the brightness of a star that are caused by a planet passing in front of it.
Exoplanets are difficult to see directly from Earth. Because they are so small and faint, they are easily lost in the glare of the bright stars they orbit, so we often use indirect methods to find them. One of these is called the “transit method”, where we carefully measure the brightness of a star over a long period of time, and look for periodic decreases in the brightness of a star that are caused by a planet passing in front of it.
Below is a Video on exoplanet discovery:
Source and Credits: Harvard