Astronomers have discovered a unique giant exoplanets.
An international team of astronomers from Europe, Iran, and Chile conducted a detailed study of the found exoplanets EPIC212521166b.
Scientists have discovered that this planet is absolutely unique phenomenon, because with sizes close to the gas giants, it is denser solid planets such as Earth.
It is noted that the composition and evolution of the newfound body is so unusual that at this point we can only build hypotheses about what caused his radical differences from any other known planet.
So far, all discovered planet in our system, and beyond, in General, fit in a clear planetary limits. Thus, the gas and ice giants like Neptune or Uranus are formed farther from the star than the hard and rocky planet like Earth or Venus. Accordingly, the outer giant planets have experienced lower temperature during formation and therefore contain more light gases than the inner rocky planets. In the end, although the same Neptune is about four times bigger than Earth in diameter, mass he is superior not to 64 times, but only in 18. Its average density is only 1.6 grams per cubic centimeter, not 5.5 grams per cubic centimeter, as of the Earth. Because of this the gravity on the surface of both these bodies are extremely close, although by weight they differ almost twenty times.
Using data from the extended mission of the space telescope “Kepler” precision and an echelle spectrograph HARPS, the researchers found that this previously considered universal pattern has an exception.
EPIC212521166b planet , revolving at a distance of 15 million miles from the orange star, is the anomalous parameters. When the diameter is 2.6 times larger than the earth (one and a half times less than Neptune), it weighs 18.3 times more of our planet, that is even more than Neptune or Uranus. Because of this, its density is equal to 5.7 gram per cubic centimeter, and gravity can be stronger than any planet in the Solar system.
This is all very unusual for such a large body, and means that for some reason re-studied exoplanet is extremely poor in hydrogen, helium and light elements in General.
By calculations of astronomers, it may be a hydrogen atmosphere with a mass of less than 0.2 of the earth. For the planets of large size is extremely small. The presence of normal amounts of hydrogen are eliminated, and the body is so close to its star that it is heated to high temperatures. Whether he has a substantial hydrogen atmosphere, it would have swollen up and gave a much larger observed diameter.
Scientists have tried to calculate whether the high density of the planet to be associated with its high temperature, which causes the atmosphere to actively lose hydrogen. As it turned out, and it is possible. Although the parent star is EPIC212521166 there are 8 billion years, at the end of simulation it turned out that all this time she couldn’t deny the planet even one percent of its weight.
Astronomers say that such a massive planet except hydrogen needs to hold a lot of water. According to the calculations, with the usual core of heavy elements (like Earth) it may consist of half water. It contains nine Earth masses in the form of water and the same in heavy rocks. If so, hydrogen in the atmosphere there either no at all or even less than in the first scenario.
However, the planet is unusual and is unlikely to look like the world-ocean, like a number of other exoplanets. The fact is that due to the high temperatures its atmosphere would consist of water vapor, and the water surface will be heated to high temperatures — the water there will be in the condition when the difference disappears between liquid and gaseous phases. The easiest way to imagine a phase in the form of a pair of superdense. Moreover, under the powerful layer of the ocean supercritical water at depths greater than 100 kilometers would be much more powerful layer of exotic ice. It can withstand high temperatures without melting, from which he holds a huge pressure.
Astronomers say that regardless of, exactly how on this planet is water and hydrogen, its average density creates a very big question about how in General can form a similar body.
It is unclear why such a powerful gravity has not led to dominance in its composition of light elements. Actually EPIC212521166b largely erasing a solid boundary between giant planets the composition of which is dominated by gas and small solid planets like Earth.
If the formation of such bodies is possible, it remains unclear why among the thousands of known exoplanets so far, only one shows such unique settings, and that allowed her to receive them. All these issues require further study and theoretical study, scientists believe.
