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Astronomers have calculated the number of complete “Earth twins” in the Galaxy.
“In recent years, dozens of articles have been published, the authors of which tried to estimate the number of Earth-like planets. None of them, unfortunately, did not take into account the fact that there may be several planets in one star, and did not use the full catalog of data from the Kepler telescope. We took into account these shortcomings and prepared a strategy for finding such worlds, ” the scientists write.
Over the past few years, the Kepler and CoRoT orbiting telescopes, as well as their terrestrial counterparts, have discovered more than four thousand exoplanets and a similar number of possible candidates for this role. Most of them are among the ” hot ” Jupiters, but new techniques allow you to find more and more minor planets.
The growing number of potential Earth counterparts, on whose surface water in liquid form may exist, is increasingly forcing scientists to think about how much of them can support life, how often they are found and where to look for them.
Danley Hsu of the University of Pennsylvania (USA) and his colleagues tried to get an accurate answer to the last two questions using images collected by Kepler and another space observatory, the GAIA stargazer probe.
The first device, as the researchers note, quite accurately calculated the number of planets similar to Earth in the constellation of Cygnus and Lyra, and the second mission – found out how many “twins” of the Sun are found in our Galaxy. Combining their data, the astronomers created a computer model of the Milky Way and calculated the number of” cousins ” of our planet, using advanced statistical methods.
To do this, they created many randomly expanded versions of this model and selected from them those in which the proportions of different types of planets were closest to what Kepler saw during its work in orbit. After several generations of such “artificial selection”, they received a virtual Galaxy that coincides in appearance with its real counterpart.
Using this data, they calculated the number of planets whose mass and size were close to Earth’s, and the year lasted from 300 to 500 days. It turned out that there are quite a lot of them – every fifth or tenth star that looks like the Sun should have at least one such companion.
Many of them, as the calculations of scientists show, will not have the Earth’s climate and appearance, but will more resemble its two closest neighbors — the less cold and distant Mars, as well as the less hot Venus.
Interestingly, Earth-like planets orbiting very close to the sun turned out to be very rare, despite the fact that Kepler and other telescopes have discovered several dozen similar worlds in other types of stars.
On the other hand, planets in the orbits of Mars and the asteroid belt should occur very often – each “cousin” of the Sun should have one or two similar satellites. All this, as noted by scientists, suggests that the search for such planets, previously considered not a very rational occupation, in fact, can and should be carried out.
To do this, it is necessary to create such methods for detecting exomeres that would be best suited for working in that part of the near-stellar space where the maximum number of Earth’s twins is concentrated, the scientists conclude.