Beyond our Solar System: On the Discovery of Exoplanets
Methods for exoplanets discovery, current status, and future exoplanetary space missions
“Generally speaking, exoplanets can be any size, and they are found in a wide range of orbits. Some have massive gas atmospheres; others are smaller with an icy or rocky composition. “— Debra Fischer
So far we have discovered more than 4000 planets around other stars. Approximately 1/3 of those are Gas giants, 1/3 Neptune-like, and 1/3 are Super Earths. A few are Terrestial.
Gas giants and Neptune-like planets are planets that mostly consist of a gaseous atmosphere and there is no visible surface.
Super Earths are nothing like what we know from our own solar system. They are much heavier than our rocky planets yet lighter than the gas giants. They might have a rocky surface or it might be mostly gas.
It might be surprising that we have discovered so few terrestrial planets — e.g. planets that are Earth-like in size and mass. The reason for this might not necessarily be that those planets are rare, but rather that small exoplanets are hard to discover. We’ll see why later in…
