The discovery of the planet was detailed in a new study that will be published in a future issue of The Astronomical Journal.

"Even though TOI 1231 b is eight times closer to its star than the Earth is to the Sun, its temperature is similar to that of Earth, thanks to its cooler and less bright host star," said study coauthor Diana Dragomir, an assistant professor in the University of New Mexico's department of physics and astronomy, in a statement.

"However, the planet itself is actually larger than earth and a little bit smaller than Neptune -- we could call it a sub-Neptune."

Why this exoplanet might have clouds

The researchers were able to determine the planet's radius and mass, which helped them calculate its density and infer its composition.

The exoplanet has a low density, which suggests it's a gaseous planet rather than a rocky one like Earth, but scientists don't yet know for certain the composition of the planet or its atmosphere.

"TOI-1231 b is pretty similar in size and density to Neptune, so we think it has a similarly large, gaseous atmosphere," said lead study author Jennifer Burt, a postdoctoral fellow at NASA's Jet Propulsion Laboratory in Pasadena, California.

"TOI1231b could have a large hydrogen or hydrogen-helium atmosphere, or a denser water vapor atmosphere," Dragomir said.

"Each of these would point to a different origin, allowing astronomers to understand whether and how planets form differently around M dwarfs when compared to the planets around our Sun, for example."

The researchers believe TOI-1231 b has an average temperature of 140 degrees Fahrenheit (60 degrees Celsius), which makes it one of the coolest of the small exoplanets available for future study of its atmosphere.

"Compared to most transiting planets detected thus far, which often have scorching temperatures in the many hundreds or thousands of degrees, TOI-1231 b is positively frigid," Burt said.

The cooler the exoplanet, the more likely it is to have clouds in its atmosphere.