A superhabitable world is a hypothetical type of planet or moon that is better suited than Earth for the emergence and evolution of life. The concept was introduced in a 2014 paper by René Heller and John Armstrong, in which they criticized the language used in the search for habitable exoplanets and proposed clarifications. The authors argued that knowing whether a world is located within the star's habitable zone is insufficient to determine its habitability, and that the prevailing model of characterization was geocentric or anthropocentric in nature. Instead, they proposed a biocentric model that prioritized characteristics affecting the abundance of life and biodiversity on a world's surface.

If a world possesses more diverse flora and fauna than there are on Earth, then it would empirically show that its natural environment is more hospitable to life. To identify such a world, one should consider its geological processes, formation age, atmospheric composition, ocean coverage, and the type of star that it orbits. In other words, a superhabitable world would likely be larger, warmer, and older than Earth, with an evenly-distributed ocean, and orbiting a K-type main-sequence star. In 2020, astronomers, building on Heller and Armstrong's hypothesis, identified 24 potentially superhabitable exoplanets based on measured characteristics that fit these criteria.

A star's characteristics are a key consideration for planetary habitability. The types of stars generally considered to be potential hosts for habitable worlds include F, G, K, and M-type main-sequence stars. The most massive stars—O, B, and A-type, respectively—have average lifespans on the main sequence that are considered too short for complex life to develop, ranging from a few hundred million years for A-type stars to only a few million years for O-type stars. Thus, F-type stars are described as the "hot limit" for stars that can potentially support life, as their lifespan of 2 to 4 billion years would be sufficient for habitability. However, F-type stars emit large amounts of ultraviolet radiation, and without the presence of a protective ozone layer, could disrupt nucleic acid-based life on a planet's surface.

On the opposite end, the less massive red dwarfs, which generally includes M-type stars, are by far the most common and long-lived stars in the universe, but ongoing research points to serious challenges to their ability to support life. Due to the low luminosity of red dwarfs, the circumstellar habitable zone (HZ) is in very close proximity to the star, which causes any planet to become tidally locked. The primary concern for researchers, however, is the star's propensity for frequent outbreaks of high-energy radiation, especially early in its life, that could strip away a planet's atmosphere. At the same time, red dwarfs do not emit enough quiescent UV radiation (i.e., UV radiation emitted during inactive periods) to support biological processes like photosynthesis.

Dismissing both ends, astronomers are led to conclude that G and K-type stars—yellow and orange dwarfs, respectively—provide the best life-supporting characteristics. However, a limiting factor to the habitability of yellow dwarfs is their higher emissions of ionizing radiation and shorter lifespans compared to cooler orange dwarfs. Therefore, researchers conclude that orange dwarfs offer the best conditions for a superhabitable world.

Also nicknamed "Goldilocks stars", orange dwarfs emit low enough levels of ultraviolet radiation to eliminate the need for a protective ozone layer, but just enough to contribute to necessary biological processes. Additionally, the long average lifespan of an orange dwarf (18 to 34 billion years, compared to 10 billion for the Sun) provides a more stable habitable zone throughout the star's lifetime, providing more time for life to develop.

It is necessary for the age of any superhabitable world to be greater than Earth's age (~4.5 billion years). This necessity is based on the belief that as a planet or moon ages, it experiences increasing levels of biodiversity, since native species have had more time to evolve, adapt, and stabilize the environmental conditions suitable for life. However, the eventual exhaustion of a world's internally generated heat means that there is also an upper limit to the age of any habitable world; internal cooling would lead to changes to the average global temperature and atmospheric composition. Therefore, the optimal age range for a superhabitable world would be roughly 5–8 billion years.

During the main sequence phase, a star burns hydrogen in its core, producing energy through nuclear fusion. Over time, as the hydrogen fuel is consumed, the star's core contracts and heats up, leading to an increase in the rate of fusion. This causes the star to gradually become more luminous, and as its luminosity increases, the amount of energy it emits grows, pushing the habitable zone (HZ) outward. Studies suggest that Earth's orbit lies near the inner edge of the Solar System's HZ, which could harm its long-term livability as it nears the end of its HZ lifetime.