New Type of Planet Unlike Anything in Our Solar System Discovered

An object initially thought to be a typical planet found in our galaxy has turned out to be entirely unique.

A Super-Venus Exoplanet

Enaiposha, also known as GJ 1214 b, is an exoplanet with a hazy atmosphere orbiting a red dwarf star roughly 47 light-years away from Earth. While it was once compared to a mini-Neptune, recent data from the James Webb Space Telescope (JWST) suggests it is more like a much larger version of Venus.

This discovery has led astronomers to introduce a new category called ‘Super-Venus,’ making Enaiposha the first known planet of its kind.

Enaiposha is one of the most researched exoplanets, having been discovered in 2009. It has a mass and size between that of Earth and Neptune, and follow-up observations revealed a thick atmosphere.

Super-Earths and Mini-Neptunes: Common Exoplanet Types

Exoplanets in this mass range typically fall into two categories. Super-Earths are terrestrial planets larger than Earth and typically have hydrogen-rich atmospheres, if they have one at all. In contrast, mini-Neptunes are also similar in size but have very different compositions, often with denser hydrogen and helium-rich atmospheres, possibly containing liquid oceans. Mini-Neptunes are the most abundant type among the 5,800 confirmed exoplanets, although we have no direct analogs in our Solar System.

Both Super-Earths and mini-Neptunes are of particular interest to scientists because, under the right conditions, they could potentially support life. Enaiposha is of particular interest due to its proximity to Earth, making it an ideal candidate for further study despite its inhospitable environment due to its close orbit around its star, Orkaria.

Although the planet is too hot for habitation, its proximity allows astronomers to study it in detail, providing valuable insights into other similar exoplanets. However, Enaiposha presents challenges due to its thick atmosphere, making it difficult to observe clearly. A 2023 study using data from JWST and Hubble revealed that the exoplanet may have a water-rich atmosphere with vaporized metals.

New research, led by astronomers Everett Schlawin and Kazumasa Ohno, has uncovered further unexpected findings. By analyzing transit data for Enaiposha, the team discovered that as the planet passed in front of its star, the starlight passing through its atmosphere showed signs of carbon dioxide, much like Venus, though the signal was faint.

Theories and Models: Explaining Enaiposha’s Atmosphere

To confirm this, the team conducted theoretical modeling and found that the best explanation is that Enaiposha’s atmosphere is dominated by metals at lower altitudes, with only small amounts of hydrogen. At higher altitudes, the atmosphere is hazy with aerosols and carbon dioxide. This led to the idea of a ‘Super-Venus’—a hot world with a dense, carbon-rich atmosphere that obscures the view.

However, the faint CO2 signal means further research is necessary to validate the findings, as this new theory challenges conventional understanding of sub-Neptunes. The researchers emphasize the need for high-precision follow-up observations to confirm the presence of a metal-dominated atmosphere and refine our understanding of these planets’ interior structure and evolution.

Read the original article on: Science Alert

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