Harvard University scientists say they've found the smallest mass a planet could be before it could lose its atmosphere and liquid water. Estimated at about 2.7 percent of the mass of the Earth, this number is the equivalent of more than twice the mass of the Moon. While this presents another possibility to widen the horizon for new planets to consider for life support, size is just another factor in a planet’s habitability, as ScienceAlert detailed:
An exoplanet is said to be in a star's habitable zone if it's at the right distance to be able to support liquid water. If it's too close, it would receive too much radiation from its sun, making it too hot. Too far, and it'd be too cold for liquid water.
"When people think about the inner and outer edges of the habitable zone, they tend to only think about it spatially, meaning how close the planet is to the star," astronomer Constantin Arnscheidt, lead author of the paper describing the research, published in The Astrophysical Journal in August, told Astrobiology Magazine.
"But actually, there are many other variables to habitability, including [a planet's] mass."
image credit: NASA/JPL-Caltech via ScienceAlert