The more than 5,000 exoplanets confirmed so far can be labeled into very specific categories. Some are super-Earths, mini-Neptunes, ice giants or gas giants, depending on their size, mass, temperature, composition or atmospheric presence. No one said that categorization was complete. After decades of planetary research, scientists have found a new type of body: the supervenus.
Supervenus are rocky exoplanets larger than Earth, but with a dense atmosphere of carbon dioxide (CO2). In the solar system there is no body with these characteristics. After several years of debating the components of the exoplanet GJ 1214b, it is finally confirmed that it is the first to present signs of a supervenus. The results were published in the journal The Astrophysical Journal Letters.
The nature of GJ 1214b is mostly unknown. It is located 48 light years from the solar system in the constellation Ophiuchus. Although it has the behavior of a planet and it is possible to observe it as it passes in front of its parent star, with its shadow it was only possible to intuit its size, orbit speed and mass.
A team of scientists from the University of Arizona and the National Astronomical Observatory of Japan wanted to define what kind of exoplanet GJ 1214b was. They used the power of NASA’s James Webb Space Telescope to observe the type of atmosphere that surrounded it. During the transit between a planet in front of its star, the components that surround it are exposed. In the hypothesis, the exoplanet had to be a super-Earth or a mini-Neptune. The data obtained did not belong to any of the categories.
There was no hydrogen or water, but concentrations of carbon dioxide as on Venus. The scientists applied a second study to confirm what James Webb had glimpsed. Computer models maintained that it was CO2 that enveloped the exoplanet. They had found an exotic planet outside the solar system and the only thing that can be compared to it is what astronomers have classified as “Earth’s evil twin.”
Venus is the second closest planet to the Sun, only surpassed by Mercury, but it has a higher temperature than it. If a person stood on the surface they would face a temperature of 467° C. For comparison, on Earth, water boils at 100° C. Venus’s high temperature is due to its dense atmosphere of carbon dioxide. carbon that surrounds the body in an eternal greenhouse effect.
According to the available documentation, Venus has this atmospheric composition due to a combination of geological and chemical factors. The planet probably housed liquid water like on Earth, but its proximity to the Sun caused its evaporation and subsequent division between its components. The hydrogen would have escaped into space while the oxygen remained to combine with carbon to form carbon dioxide. In addition, it has high volcanic activity that releases a large amount of CO2.
The most common classes of exoplanets are in a size range between Earth and Neptune. When they encounter a body of those dimensions, astronomers debate whether they are rocky Earth-like planets with thick hydrogen-rich atmospheres, or icy Neptune-like planets surrounded by water-rich atmospheres, called water worlds. Now a third type must be included: the superneptunes.
#Astronomers #discover #type #exoplanet #supervenus
