Astronomers have discovered an Earth-sized planet 11 light years away

Since Ross 128b is the second most distant planet from our solar system, it could serve as a target for the search for life.

Astronomers have discovered an Earth-sized planet 11 light-years away known as Ross 128b. It is the second known planet at a distance from our solar system, it could be used as a target for the search for life after the closest planet - Proxima b seems less suitable for life. This is because Proxima b, which was discovered in 2016, orbits a red dwarf - a very active star, and numerous eruptions hit the planet and bring with it harmful radiation.

The new star, Ross 128 b, orbits a star not unlike Proxima Centauri (also a red dwarf), but significantly less active. It was recently discovered using radial velocity instruments at the La Silla Observatory in Chile. The study was published in the journal Astronomy and Astrophysics.

Red dwarfs are the coldest and faintest stars, but precisely because of this they are the most common objects in the universe. This fact makes them very good targets in the search for planets outside the solar system and therefore there is a lot of research around them. The author of the article Bonfis Xavier (Institut de Planétologie) from the Department of Astrophysics at the University of Grenoble in France says: "Even so it is easier to discover planets the size of the Earth around red dwarfs than around suns like ours."
Nicolas Estudillo-Defro from the Geneva Observatory, who is also a partner in the research, said: However, we must examine the atmosphere of Ross 128 b, to examine whether this planet is friendly to life and contains water in a liquid state like Earth or perhaps devoid of life and water like Venus.
Describing the finding, the lead author of the study, Xavier Bonfis, Institute of Planetology, Astrophysics, Grenoble (IPAG), France, told BBC News: "Ross 128 is one of the quietest stars in the sample, although it is slightly larger than us (2.6 x), It makes a great alternate target.”

The mass of Ross 128 b is about one third that of the Earth and it is also slightly larger than the Earth. However, due to the fact that it orbits a small and cold star, in order for it to be in the habitable zone, its orbit is 20 times closer than the Earth's orbit to the Sun, but it receives only slightly more solar radiation than the Earth. As a result, it is expected to have a surface temperature close to that of our planet.
Most of the 3,500 known planets are of the "hot Jupiter" type, gas giants like Jupiter, but orbiting close to their sun, so there are no conditions for life there. Most of the Earth-sized planets discovered so far orbit red dwarfs - the most common type of star in the Milky Way. Because the stars in this category are faint, this makes it easier for astronomers to discover relatively small planets when they pass between us and their sun.

The habitable zone is the range of distances from the star where the temperatures allow water to remain in a liquid state on the surface of a planet. Where that area is located depends on the central star of the system. Red dwarfs are fainter and cooler than the Sun, so their habitable zones will be moved closer to the star. It is still unclear if Ross 128 b is in the habitable zone, but scientists estimate that the temperature on its surface may be in the range between 20 degrees Celsius and 60 degrees.

In the next step, the astronomers want to study the composition of the atmosphere and the chemistry of the planets that have the potential to accommodate life, and are relatively close to us like Ross 128 b. The detection of gases such as oxygen in the atmosphere may indicate biological processes.

According to Estudillo-Defro, there is still a debate about what the best biomarkers are. Currently, molecular oxygen (O2) and ozone (O3) are good markers. Other gases such as carbon dioxide or methane can also be formed from geological events. "For sure we will look for all these gases as well as water vapor."

So far, a number of gases have already been detected in the atmospheres of planets outside the solar system, but the ability will be improved in the next decade through the European Southern Observatory's Very Large Telescope Observatory (ELT), and the James Webb Space Telescope (JWST) which will start operating in the coming years.

According to Bonfis, when these two facilities become operational, this will give astronomers the collecting power and angular resolution to directly observe Ves 128 b "We will be able to see if it has an atmosphere and, if so, whether it contains oxygen, water and methane," Bonfis concluded.

for the scientific article

to the announcement of the European Space Agency