Fomalhaut

Fomalhaut is a Class A main sequence star, much brighter and about twice the size of our G-Type Sun. A bright star in the night sky, Fomalhaut is in the constellation Pisces Australis in the southern sky and is around 25 light years from Earth.

Fomalhaut exhibits a ring of dust and debris like the asteroid belt or the Kuiper belt. The asteroid belt orbiting the Sun is between Mars and Jupiter while the Kuiper Belt is beyond the orbit of Neptune. Beyond that is the Oort Cloud which has a diameter of roughly two light years, while the ring of debris around Fomalhaut most studied is more like the Kuiper Belt with a diameter of two one thousanths of a light year. Earths orbit is fifteen millionths of a light year, Neptunes orbit has a radius of about 4.1 ‘light-hours’ or .5 thousanths of a light year.

In light years, these numbers are small, so for the Fomalhaut system and our Solar System scientists talk in terms of Astronomical Units, or AU. One AU is the distance from Earth to the Sun. Neptune is 30.1 AU from the sun, or 30 times further. The outermost studied cloud of debris around Fomalhaut is 133 AU, or four times greater in orbit radius than the orbit of Neptune. But since Fomalhaut is 20 times brighter than our Sun and of much greater mass, the inhabitable zone for a Fomalhaut earth like planet would have an orbital radius of three to five AU.

Additional dim stars around Fomalhaut taken by the Hubble Space Telescope lead scientists to call it a triple star system, with ‘B’ and ‘C’ stars that yield little luminosity and are around one light year or 65,000 AU away, well outside the known debris belts of Fomalhaut.

Within the debris field, scientists have detected two planets roughly the size of Earth. However, one is thought to be Mars like with lower gravitational force and the other twice earth with a greater gravitational pull. Because they are so far outside the three to five AU habitable zone, they are thought to be very cold planets.

In order to take advantage of the habitable zone of Fomalhaut, we could conceive of an Elysium style satellite but with an additional twist. The elliptical orbit of Fomalhaut B leads scientists to believe that the inhabitable zone will be heavily bombarded with asteroids and meteorites.