The mystery of the missing super-Earths and mini-Neptunes may finally be solved

Super-Earths or mini- Neptunes appear to be missing in space.

They're classified as larger than twice the size of Earth , but smaller than Neptune .

The absence of these planets has become known as the "radius gap" The most common explanation for the gap is that stars irradiate the planets that closely surround them, stripping the atmospheres of those worlds and causing them to shrink.

But new research suggests planets may have taken different routes out of the valley .

Both mechanisms result in a dearth of planets around twice the width of Earth .

The team's simulations used to potentially unravel this mystery could also have an impact in other areas of exoplanet science.

The research was published Feb. 9 in the journal Nature Astronomy .