A recently discovered gaseous planet called NGTS-4B – or better known as the “Forbidden Planet” – is almost the same size as Neptune (20% smaller than Neptune and three times the size of Earth) and is around 920 light years away from Earth. There’s one major problem with this planet: it shouldn’t exist.
Located in a region of space called the “celestial desert”, the planet has a surface temperature of 1,000 degrees Celsius (or 1,832 degrees Fahrenheit). With a temperature that hot, the atmosphere on the planet should have evaporated since it’s so close to its star. But incredibly it still exists and it orbits around its star every 1.3 days.
It’s also the first exoplanet to have been discovered in the Neptunian Desert, which is an area close a star where no Neptune-size planets have ever been located. Being that close to its star, the planet’s gaseous atmosphere should be completely evaporated; leaving it with nothing more than a rocky core, but NGTS-4B still contains its gassy atmosphere.
It was first discovered when telescopes that were run by the University of Warwick noticed the planet when it passed in front of its star as the brightness of the star dimmed by 0.2 percent. Researchers are baffled as to why the planet remains in existence being so close to its star. They do, however, have some theories, such as the planet ended up in its current position within the last million or so years; or that the planet was once much bigger than it currently is and it’s continuously getting smaller as the atmosphere is evaporating.
Dr. Richard West, who works in the Department of Physics at the University of Warwick, said, “This planet must be tough – it is right in the zone where we expected Neptune-sized planets could not survive,” adding, “It is truly remarkable that we found a transiting planet via a star dimming by less than 0.2 percent – this has never been done before by telescopes on the ground, and it was great to find after working on this project for a year.”
This incredible discovery has researchers looking for more possible Neptune-sized planets surviving so close to their host star. “We are now scouring out data to see if we can see any more planets in the Neptune Desert – perhaps the desert is greener than was once thought,” West stated.