New celestial object unlike anything else in the Solar System discovered

Astronomers have used data from the James Webb Space Telescope to reveal shocking insights into an exoplanet that with an unexpected composition that has led to a new category.

The exoplanet Enaiposha, also known as GJ 1214 b, has a thick and hazy atmosphere. Initially believed to be a water world, a recent study of the planet’s internal structure suggested this would be implausible. First discovered in 2009, Enaiposha is one of the most studied exoplanets and is unlike anything else in our Solar System.

It was previously referred to as a mini-Neptune, as the actual Neptune is an ice giant planet. Enaiposha is larger than Earth - 2.7 times the radius and 8.2 times the mass of our home planet - but smaller than Neptune.

Mini-Neptunes and super-Earths are both categories of exoplanets that interest astronomers because if other conditions are just right, they might be able to harbour life. Enaiposha is far too close to its host star, Okaria, to be able to host life itself as the planet would be far too hot.

New in-depth observations using the James Webb Space Telescope data suggests it is much more similar to Venus, the hottest planet in the Solar System. However, Enaiposha is believed to be much larger than Venus, which would make it the first known planet of its kind.

Astronomers are referring to this new category as ‘super-Venus’ and Enaiposha is unlike anything else in the Solar System. Scientists can potentially gather information about it that could aid our understanding of other exoplanets and how they function. Alas, there are still some problems at hand with observing Enaiposha, which is 47 light-years from Earth, as its atmosphere is so thick, it can’t be seen very easily.

Artist’s impression of GJ 1214 b passing in front of its host starNAOJ

New research led by astronomers Everett Schlawin at the University of Arizona and Kazumasa Ohno at the National Astronomical Observatory of Japan has shed more light about this mysterious exoplanet. A team of researchers studied transit data for Enaiposha and discovered that as it passed in front of Okaria, starlight travelling through the exoplanet's atmosphere was altered by similar concentrations of carbon dioxide that makes up more than 96 per cent of Venus’ atmosphere.

"The detected CO2 signal from the first study is tiny, and so it required careful statistical analysis to ensure that it is real," Ohno explained via NAOJ. "At the same time, we needed the physical and chemical insights to extract the true nature of GJ 1214 b's atmosphere."

The researchers aimed to conduct theoretical models that could explain the data, which they analysed in a second paper. The scenario that was the best fit for their observations is that Enaiposha has an atmosphere dominated at lower altitudes by metals, and only relatively small amounts of hydrogen. The reading implied the atmosphere consists of a haze made dense with aerosols and CO2 at higher altitudes.

This is where the super-Venus idea stems from — a planet that is very hot with a carbon-rich atmosphere through which it is difficult to see. "We stress the importance of high precision follow-up observations to confirm the metal-dominated atmosphere," the researchers cautioned, “as it challenges the conventional understanding of interior structure and evolution of sub-Neptunes."

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