When it comes to Neptune, it is certainly not a unique planet. Closely identical exoplanets and those gas giants that are much larger than Earth are believed to be the most common planets in the universe. However, when get too close to their sun; they are bombarded with stellar radiation that dries up all of their gaseous atmospheres, leaving behind a barren desert.
This is not the case with this planet, which is called the Forbidden Planet—and was once referred to as NGTS-4b. It is presently in a Neptunian-like desert mode, as it is way too close to its host star and has an incredible orbit of only 1.34 days.
What an Amazing New Study Revealed
However, researchers from the Royal Astronomical Society are now reporting that it is still retaining its Neptune-like atmosphere – according to a recent study. It is the very first detection of a Neptunian-like exoplanet that has defied the odds and residing near its host star.
“As far as we are aware, it is the first exoplanet of its kind to have been found in the Neptunian Desert,” stated Ed Gillen, who is an astronomer from the University of Cambridge and also a coauthor from this recent study. ”It seems as though the Neptunian desert is not completely dry, so we are now searching our data for other similar planets to help us understand whether it is greener than was once thought.”
It is as if this planet desert is barren: “we see hot and warm Jupiter-size planets, and hot and warm planets with the size of the Earth or a bit larger,” noted Vincent Bourrier, who is an astronomer from the University of Geneva who did not take part in the study. “There are even warm Neptunes. But there are no hot Neptunes very close to their stars, hence this name of ‘Neptunian desert.’” The boundaries of these planetary deserts will vary from star to star, but the effect on planets are basically the same – a loss of atmospheric gases for mid-sized gas planets (unlike a hot Jupiter, these planets lack the mass to protect their atmosphere), which turns them into rocky, bald wastelands.
How Exoplanets are Discovered
The usual way that researchers find exoplanets is to observe variability in star brightness, which indicates that a planet is orbiting in front of the host star from Earth’s point of view. Exoplanets just like NGTS-4b—they are quite small and are quite close to their host stars—are very hard to find as any dip in brightness are very small.
“Most transiting planets detected from the ground are large and hence, when they transit, they cause their stars to appear around 1 percent dimmer,” points out Gillen. “NGTS-4b is much smaller, however, causing its star to appear only 0.2 percent dimmer. To detect such a small dimming from the ground is remarkable.”
Thankfully, Gillen and his research team had at their disposal a state-of-the-art Next-Generation Transit Survey (NGTS) observing facility available. “Our telescopes are situated in the Chilean Atacama Desert, which is probably the best place on Earth to search for exoplanets,” because of the incredibly clear skies in the region, along with virtually no light pollution or any radio interference. “We also have incredibly precise telescope machinery. Both of the aspects greatly aided us to to find this planet.”
It is quite incredible to imagine how NGTS-4b has discovered the means of residing so amazingly close to its host star. It is just a bit smaller than Neptune itself, yet three times larger than Earth and 20 times heavier. It is blazing at 1,000 degrees Celsius. It is actually hotter than Mercury’s surface in the daytime.
Thus far, the most popular theories that Gillen and his research team have pondered are that perhaps the planet just moved into its current position, or that maybe it had a much larger atmosphere to begin with that is still evaporating. Or the atmosphere of this planet could be comprised of some chemistry that is unknown to us.
Regardless of the reason, this team of scientists is very eager to locate more of these gaseous Neptunian desert dwellers so that they can compare them and figure out why an atmosphere similar to NGTS-4b’s is able to survive in such harsh conditions.