Can distant planets harbour life?

A new study ( The Astrophysical Journal) describes how extraterrestrial life has the potential to exist on distant exoplanets inside a special area called the ‘terminator zone’, which is a ring on planets that have one side that always faces its star and one side that is always dark.

Such planets are particularly common because they exist around stars that make up about 70% of the stars seen in the night sky — so-called M-dwarf stars, which are relatively dimmer than our sun, says a release. The terminator is the dividing line between the day and night sides of the planet.

Terminator zones could exist in that “just right” temperature zone between too hot and too cold. On the dark sides of terminator planets, perpetual night would yield plummeting temperatures that could cause any water to be frozen in ice. The side of the planet always facing its star could be too hot for water to remain in the open for long.

Researchers modelled the climate of terminator planets using software typically used to model earth’s climate, but with a few adjustments, including slowing down planetary rotation.

It is believed to be the first time astronomers have been able to show that such planets can sustain habitable climates confined to this terminator region, says the release.