Astronomers have found a star, «ate» more than a dozen twins of the Earth

© NASA/JPL-CaltechПланетная system with two suns, Kepler-16Astronomers have found a star, «ate» more than a dozen twins of the Earth© NASA/JPL-Caltech

. Planetary scientists found in the constellation Cassiopeia unusual pair of stars, one of which received a speaking name «Kronos», ate about a dozen doubles of the Earth in the last years of his life, said in an article published in the electronic library arXiv.org

«I was very impressed and pleased with what I saw when I studied the composition of these stars. As a rule, the differences in chemical composition between stars with planets and without planets are very small. In this case you can see them almost naked eye», says the opening of Johanna Teske (Johanna Teske) from the Carnegie Observatory in Pasadena (USA), quoted in the magazine New Scientist.

Stars, as shown by recent observations of dozens of groups of astronomers, may periodically destroy and «eat» the planets that revolve around them. This can occur at the earliest stages of existence, when the planets are born, and at the end of life, when the outer shell of the star swell and envelop the planet, and even after shining dies and turns into a white dwarf or a neutron star.

In the past scientists did not pay attention to such events, as they believed that they do not lead to significant changes in the appearance and behavior of stars. Recently, planetary scientists have found that it is really not «eating» the planets greatly alter the spectrum of white dwarfs and neutron stars, and can radically change the behavior of ordinary stars, making them larger and less bright.

Simon Oh (Semyeong Oh) from Princeton University (USA) and her colleagues found one of the most unusual examples of this cosmic «cannibalism» by studying a few unusual stars — HD and HD 240429 240430 – recently discovered in the constellation Cassiopeia.

These luminaries, as they say scientists, are outwardly almost indistinguishable from each other – they were formed about 4 billion years ago in the same «stellar nurseries» and since then travel across the space together while at a distance of two light years from each other. Now they are about 320 light years from Earth and are, according to some astronomers, part of the unusual binary star system, half of which do not behave as other pairs of bodies.

Oh and her colleagues tried to check if it’s actually as HD and HD 240429 240430 there is one feature that is not allowed to say so. In the depths of the first star, as was shown by measurements of its spectrum, contains much more of certain «metals» – elements heavier than hydrogen and helium – than its «neighbor».

Titans of space

Usually, this distinction suggests that stars formed in different parts of the galaxy where clouds of interstellar gas contain different fractions of carbon, oxygen, potassium and other elements. On the other hand, the fact of the meeting of the two stars, their similar size and age they say to the contrary.

The reason for this impossible paradox, as discovered by Oh and colleagues, hiding the differences in the concentrations of various «metals» in the bowels of HD 240430 and its more «clean» roommate. Scientists have noticed that all substances, the proportion of which varies greatly, are present in large numbers in one type of celestial bodies – planets and rocky asteroids.

As the calculations of the researchers, it is luminary, named «Kronos», was supposed to eat, like the Titan from Greek mythology, more than a dozen earth-like planets and few rocky «super-earths» whose total mass is about 15 times bigger than Earth. In this case, the HD range 240430 will be as good as it looks in reality.

How could this happen? As scientists assume, «Kronos» and its sister «Krios» recently approached by another star, the gravity of which «shook» their planetary system and destabilize it. As a result, some or all of the planet fell to the «Kronos», traces of which are relatively high proportion of lithium in its matter, usually disappearing from the surface of stars, similar to HD and HD 240429 240430 in a few million years after such a «dinner.»

Now, scientists are looking for planets on the outskirts of this star system, potentially survivors of this cataclysm. Their discovery, as the scientists hope, will help us understand exactly how and when Chronos ate his children.

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