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Planet-eating twin stars Kronos discovered by astronomers

15 Octobre 2017

But the official name of Kronos is HD 240430, and that of Krios is HD 240429.

"Gravitational interactions with the passing star stretched the orbits of Kronos' outermost planets so that they ended up passing through the inner planetary system", they explained.

HD 240430 is nicknamed Kronos because it is quite likely the planets it consumed were a part of its system. The character is known for eating his children, including Poseidon (better known as the planet Neptune), Hades (Pluto) and his three daughters. Not that the planets, in this case, had any chance of threatening their parent star, but the analogy still applies. The companion star HD 240429 is named Krios, after Kronos' brother.

Both stars are 4 billion years old, and like our own, slightly older Sun, both are yellow G-type stars. Comparing their datasets-hers of information on binary stars and his on stars' chemical composition-the researchers identified Kronos and Krios, which appeared in both the binary-star and stellar-composition datasets.

Kronos and HD 240429 (dubbed Krios) are members of a wide binary system.

A research team from Princeton University in the United States has confirmed that the two twin Stars are not very close to each other and are widely separated.

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"Even if our sun ate the entire inner solar system, it wouldn't come close to the anomaly we see in this star", said David Hogg from the Center for Computational Astrophysics (CCA) at the Flatiron Institute, who is co-author of the study describing the discovery. These materials are found in abundance in Kronos' outer layers. The lighter elements like oxygen, carbon, nitrogen, and potassium are found in the gaseous form. The heavier elements present on Kronos are said to have formed after the lighter ones as per the laws of chemistry.

Therefore, usually, a Kronos-like metal-rich star would contain "all the other elements enhanced at a similar level, whereas Kronos has volatile elements suppressed, which makes it really weird in the general context of stellar abundance patterns", the study's lead author Semyeong Oh, a graduate student at Princeton University, said in a statement Thursday.

Then the researchers noticed the extreme chemical differences between them.

This artist's illustration shows a planet-eating star.

Some 350 light years away from Earth, astronomers have spotted an extraordinary sun-like star that has consumed 15 rocky planets in its own system. In turn, their gravity sent rocky inner planets crashing into the star.

Jessie Christiansen, an astronomer at the NASA Exoplanet Science Institute at the California Institute of Technology, who was not involved in the research, gave examples of Kepler-11 and HD 219134, stars that have over 22 and 15 Earth masses of material respectively on the planets that orbit them.

Planet-eating twin stars Kronos discovered by astronomers