Astronomers have discovered a bizarre, Neptune-sized exoplanet located less than 100 light-years from Earth that's shedding its atmosphere so quickly it may help researchers finally answer the long-standing question: Where did all the hot Neptunes go?

According to the new research, which was published December 13 in the journal Astronomy and Astrophysics, the shrinking world, named GJ 3470b, is rapidly losing its atmosphere as it's bombarded by a steady stream of energetic charged particles from its red dwarf host.

The discovery — made with the help of NASA's indefatigable Hubble Space Telescope — suggests that although Neptune-sized exoplanets can exist temporarily very near their host stars, they may not last very long. Instead, these planets could lose a significant fraction of their mass through evaporation driven by intense stellar winds. In the case of GJ 3470b, the researchers think strong winds from its active host star have stripped the planet of up to about 35 percent of its original mass over the course of its life.

"This is the first time a planet has been observed to lose its atmosphere so quickly that it can impact its evolution," said lead author Vincent Bourrier, an astronomer from the University of Geneva (UNIGE), in a press release.

An oasis in the desert

Based on our own solar system, astronomers typically break down planets into three broad categories: rocky terrestrial planets (like Earth and Mars), massive gas giants (like Jupiter and Saturn), and freezing ice giants (like Uranus and Neptune). But over the years, researchers have discovered a multitude of exoplanets around other stars that seem to break these familiar molds.

In particular, since the first confirmed exoplanet was discovered just a few decades ago, researchers have uncovered a surprising number of giant planets, dubbed hot Jupiters, located extremely close to their host stars. On the other end of the spectrum, astronomers have discovered a plethora of hot super-Earths, which are a few times the mass of the Earth, that sit very near their stars. However, astronomers very rarely find medium-sized planets (or hot Neptunes) in similar close-in orbits.

But why does this void of hot, mid-sized planets — the so-called "hot Neptune desert" — exist?