Defining the Really Habitable Zone

Abstract

Since the discovery of the first confirmed exoplanet, observations have revealed a remarkable diversity of worlds. A wide variety of orbital and physical characteristics are detected in the exoplanet population, and much work has been devoted to deciding which of these planets may be suitable for life. Until now, though, little work has been devoted to deciding which of the potentially habitable planets might actually be worth existing on. To this end, we present the Really Habitable Zone (RHZ), defined as the region around a star where acceptable gins and tonic are likely to be abundant. In common with much of the work in the field, we rely throughout on assumptions which are difficult if not impossible to test and present some plots which astronomers can use in their own talks, stripped of all caveats. We suggest that planets in the Really Habitable Zone be early targets for the JWST, because by the time that thing finally launches we're all going to need a drink.

The Parking Lot Planet

“…In the same spirit as defining the Habitable Zone, a region of the planetary system where liquid water can exist, Pedbost et al (2020) did a very exhaustive study for the Really Habitable Zone, using the requirement of perfect gin and tonics. This translates to a requirement of effective stellar flux at the semimajor axis of the planet, and so the region depends on the type of star considered.…”

“…This translates to a requirement of effective stellar flux at the semimajor axis of the planet, and so the region depends on the type of star considered. We adopted constants from Table 1 in Pedbost et al (2020) and estimated this region for a star of mass 0.5M . This stellar mass gives the planets in this region an ideal synodic period of nearly 1 year, perfect for a summer vacation.…”

“…This is the zone where water can exist in liquid form and it changes depending on the type of star we are considering. Furthermore, to make things more pleasant for future visitors, we would like to use the definition of the Really Habitable Zone (Pedbost et al 2020), which is the zone where acceptable gin and tonics can exist (for parents, of course).…”