X is for Xenoplanets

υ  Andromedae d and its potential moons

Xenoplanet is a bit of an odd term. It's the same as "extrasolar planet" and "exoplanet". All of these terms refer to planets orbiting stars other than our own Sun. They come in all shapes and sizes, from gas giants larger than Jupiter to rocky planets about the size of Earth.

The dream of astronomers and astrobiologists in particular is to find a planet in a star's habitable zone with atmospheric properties very similar to Earth's. This planet could potentially harbor some form of life.

Of course, this "planet" could actually be a moon, if the primary planet orbits the sun at a close enough distance.


Image from Wikipedia - υ Andromedae d.