Astronomers have discovered an earth-like temperate planet just 11 light years from Earth. The new world was named Ross 128 b. After Proxima b, this is the second closest to us earth-like planet with a temperate climate (hereinafter we mean not an analogue of a temperate climate on Earth, but a temperature favorable for the existence of potential life). It is also the closest exoplanet orbiting an inactive red dwarf, making it more likely to find hypothetical life on it. The discovery is described in an article published in the journal Astronomy & Astrophysics.
Red dwarfs are among the coldest and faintest - but also the most common - stars in the universe. It is believed that they make up about 70 percent of the total number of stars in spiral galaxies and about 90 percent of the stars in elliptical galaxies. This makes them very attractive objects for searching for exoplanets, and they are being studied more and more often. In addition, near such stars, it is easier to see celestial bodies similar to the Earth than in stars like the Sun. The fact is that red dwarfs are smaller in size than our star, so the planets that revolve around have a more noticeable gravitational effect on them than the same objects next to larger stars like yellow dwarfs. As a consequence, changes in the radial velocity of a red dwarf are easier to measure.and this is one of the most common ways to find exoplanets.
A team led by Xavier Bonfils used the ESO HARPS receiver at La Silla Observatory in Chile to study the red dwarf Ross 128. It is a very small and cool star, with a mass of only 0.16 solar and an effective surface temperature of 3192 kelvin (in the Sun it is almost twice as large). Scientists found that an exoplanet with a mass of about 1.35 Earths revolves around it with a period of about 9.9 days. Even though Ross 128 b is 20 times closer to its parent star than the Earth is to the Sun, it receives only 1.38 times more energy on its surface than the surface of our planet. As a result, it turns out that if the planet Ross 128 b has the same atmosphere as Venus, then the equilibrium temperature is estimated at −4 degrees Celsius, and if, like the Earth, then at −60 degrees Celsius. If the atmosphere is more rarefied, then it can be heated up to +20 degrees Celsius. Although these conditions can be called moderate, it is not entirely clear whether Ross 128b lies inside, outside or on the border of the habitat, that is, whether liquid water can exist on its surface. Different studies give different estimates of the size of the habitable zone, much depends on what the gas shell of a celestial body will be like. In their work, the authors say that it is better for the time being to call Ross 128b a temperate planet than a potentially habitable planet. Different studies give different estimates of the size of the habitable zone, much depends on what the gas shell of a celestial body will be like. In their work, the authors say that it is better for the time being to call Ross 128b a temperate planet than a potentially habitable planet. Different studies give different estimates of the size of the habitable zone, much depends on what the gas shell of a celestial body will be like. In their work, the authors say that it is better for the time being to call Ross 128b a temperate planet than a potentially habitable planet.
Data from the All Sky Automated Survey (ASAS) and the K2 mission show that Ross 128 rotates slowly and has weak magnetic activity. This means that it is much quieter than, for example, Proxima Centauri, and therefore its planets are probably the closest to us, on which it is hypothetically possible to support life. Now the star Ross 128 is 11 light years away, but it is moving in our direction, and according to calculations, in just 71 thousand years it will become our closest space neighbor, and the planet Ross 128 b is the closest exoplanet to Earth instead of Proxima b.
In recent years, astronomers have discovered more and more exoplanets with moderate surface temperatures, and the next stage of their study should be a detailed study of the structure and chemical composition of their atmospheres. Astronomers hope to see biomarkers in the gas envelopes of nearby exoplanets, such as oxygen. In the future, this is likely to be done by the Extremely Large Telescope (ELT) under construction at ESO. Other instruments, including the James Webb Telescope, which will be launched soon, will be expensive to explore. In addition, Ross 128b does not transit, which means that the method of "scanning" the atmosphere is no longer necessary.
“ESO's new tools will play a pivotal role in characterizing Earth-like exoplanets. In particular, the efficiency of observations of red dwarfs, which emit mostly in the infrared range of the spectrum, will increase dramatically when the infrared attachment to the HARPS spectrograph: the NIRPS receiver is activated. And, of course, the ELT supertelescope will play the first violin in these studies,”concludes Xavier Bonfi.
Recently discovered exoplanets include Proxima Centauri b and TRAPPIST-1 planets, all orbiting red dwarfs. Scientists have repeatedly said that powerful flares occur on stars of this type, which means that conditions on exoplanets may not be entirely suitable for life, even though they are in the habitable zone.
Christina Ulasovich
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