Mini-Neptunes can be altered into super-earths in the habitable zones of M dwarfs

A recent study suggests that combining tidal forces and vigorous stellar activity provides enough potential to convert uninhabitable “Mini-Neptunes” to habitable locations. A team of researchers from the Washington University has made this observation.

“Mini-Neptunes” are the big planets with solid inner core and hydrogen atmospheres; they are present in the outer orbits. Low-mass stars in the galaxy are also known as M dwarfs. Researchers tend to study them more while looking for potential outer world places that would support life. Super Earths are also such planets where scientists expect to find life supporting ingredients. They are the planets larger than Earth mass wise but smaller than Neptune and Uranus.


The lead author Luger said that tidal effects and vigorous stellar activity are the two factors that can negatively affect habitability in other planets. Tidal force can stretch a world into various shapes because it is the gravitational attachment a start has. This stretching leads to friction which gives out massive amount of energy. This energy in turn make the environment so heated that life can’t exist there.

Vigorous stellar activity is the second negative factor that inhibits life on M dwarfs. They emit heaps of X-rays and ultraviolet rays causing extensive hotness of the upper atmosphere of the planet.

But the same two factors can covert Mini-Neptunes into gas-free life supporting zones, an observation made by Luger and his group where they used many types of computer modeling.

Mini-Neptunes contain rock solid ice core surrounded by hydrogen and helium gases. Tidal force causes migration of planets, thus Mini-Neptunes start coming close to the habitable zones of their host star. This exposes them to much higher amount of X-ray and ultraviolet radiation. As a result of the whole process, a huge loss of atmospheric gases occurs. And the ice core becomes the possible source for the water. Many other factors such as nutrient recycling and creation of right atmosphere are also needed to be considered, added the researchers.

Future research will unleash further details about the process.

About the author

Nitin Agarwal

Nitin has a background in Electrical Engineering and is passionate about the Internet of Things. He covers how connected devices like smart homes, wearables, and industrial IoT are changing our daily lives. Nitin is also a DIY enthusiast and loves to build IoT gadgets.