A new perspective for Habitability and the Circumstellar Habitable Zone

Amri Wandel

Habitability is linked with the presence of liquid water. The traditional Habitable Zone (HZ) is the circumstellar region where liquid water can exist on a planetary surface. However, this definition of habitability may turn out too strict. Liquid water is present under a relatively thin ice layer on Enceladus and Europa, the moons of Saturn and Jupiter, respectively. Similarly, subglacial liquid water may be expected in exoplanets orbiting their host star outside of the traditional HZ. Combining subglacial water and climate models we extend the conservative HZ, especially for tidally locked planets of Red Dwarf stars. These planets are particularly suitable for biosignature detection using transmission spectra like those recently observed by the James Webb Space Telescope