Twenty-four planets that may possess conditions habitable for life (as we understand it) were recently identified. Not only do these planets have (potentially) the right conditions for life, in a lot of cases they appear to be superior to the conditions here on earth - and have so been dubbed super-habitable planets.
In a recently study, scientists from Washington State University identified the characteristics of planets that could support life:
Presence in habitable zone: Planets in the “goldilocks” zone, which is the region around a star where the temperature is just right for liquid water to exist on the planet.
Life expectancy of host star: The study focused on K dwarf stars, which have a longer life expectancy and therefore would allow planets that orbit it - in the goldilocks zone - enough time to develop life before they went kaput (it took over 4 billion years for complex life forms to begin making their appearance on Earth #evolution). They narrowed in on exoplanets whose host star was between 5 to 8 billion years old.
Size and mass of planets: In theory, planets 10% larger than earth and up to 1.5x more massive could have more habitable land, retain their interior heating for a longer period of time, and have stronger gravity.
Surface temperature: Life prefers warmth and moisture (just look at the biodiversity in our own planet’s more tropical climates). The study zeroed in on planets with a mean surface temperature of 5°C higher than on Earth, as this would indicate conditions for moisture, clouds and humidity - and of course water. In short, these planets are older, a little bigger, slightly warmer and wetter than Earth - making them optimal for life to thrive. Additional criteria such as land/water distribution, data on the exoplanet’s moon(s) and plate tectonics were also established. But scientists are inhibited by the technology currently available and have been unable to perform in-depth studies of all of the criteria set forth.
The researchers studied 4,500 known exoplanets (planets that orbit a star outside our solar system) and narrowed the list down to 24 planets that meet or exceed these criteria. All of the potentially super-habitable planets are over 100 light-years away from our solar system.
While none of them tick all of the boxes, they have made the short-list for further study using powerful telescopes, which are currently being developed. One of the 24 in particular has been deemed the MVP... drum roll please... an exoplanet orbiting a K-type star known as... KOI 5715.01 or KIC 9832379.
Here’s how the MVP measures up:
Presence in habitable zone: Check! The planet orbits KOI 5715 about every 190 days.
Life expectancy of host star: KOI 5715 is 5.5 billion years old, the life expectancy of K-type stars is between 20-70 billion years.
Size and mass: 1.8 times bigger than Earth.
Basically - the perfect conditions for complex life to form. But KOI 5715 isn't a hop, skip and a jump from us - it's over 2,964 light-years away from our solar system.
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Image by Guillermo Ferla