Astronomers have confirmed for the first time the existence of an atmosphere on a relatively small planet dominated by heavier chemical elements than hydrogen.
Scientists have discovered that the already known planet GJ 9827 d, which is 98 light-years away and almost twice the size of Earth, is a so-called steam world. A high concentration of water vapor was found in the atmosphere, as well as the existence of heavier chemical elements than hydrogen.
This discovery is of great importance for the search for extraterrestrial life on planets outside the solar system. The study was published in The Astrophysical Journal Letters, reports Phys.
Exoplanet GJ 9827 d was already the subject of research by scientists earlier this year. The Hubble Space Telescope confirmed that the planet has a significant atmosphere and found signs of water on it. The world, which is almost twice the size of Earth, is now the smallest known planet with an atmosphere.
Now scientists have conducted a new observation of the planet GJ 9827 d using the Webb Space Telescope and found that the water is in the form of steam, and so this object can be considered a so-called steam world.
Detecting atmospheres on relatively small planets is much more difficult than on larger rocky worlds and gas giants. It is even more difficult to detect atmospheres in which the dominant element is not hydrogen, but heavier chemical elements.
New data has shown that GJ 9827 d’s atmosphere not only contains a lot of water vapor, but also a high concentration of heavy chemical elements and compounds.
This is the first time astronomers have discovered a planet with a heavy, water-rich atmosphere, with much less hydrogen than other known worlds.
It is believed that the planet’s atmosphere may be rich in carbon dioxide and nitrogen. So it is more like the atmosphere of terrestrial planets, including Earth.
The problem is that GJ 9827 d is too close to its star to support life. The temperature of the planet is about 350 degrees Celsius. However, scientists say the new discovery is a major step forward in the search for habitable worlds.
The fact that a relatively small planet has a water-rich atmosphere supports the hypothesis that such worlds exist, meaning that Earth-like planets can be found that are habitable.
Now astronomers plan to further study the chemical composition of the atmosphere of the planet GJ 9827 d to determine what exactly it consists of.
