A team of astronomers from the University of Aix-Marseille in France announces having discovered three exoplanets located 340 light-years away from earth. One of them would be hot, metallic, the size of the Earth with a density similar to that of Mercury.
The hunt for exoplanets continues. Three new worlds have been discovered: K2-229b, c and d. The most interesting, K2-229b, which you will find about 340 light-years away in the constellation Virgo, is a little larger than Earth by about 20%. However its mass is two and a half times bigger — making it a planet more massive than Mercury. It has a surface temperature close to 2000 ° C. K2-229b orbits very close to its host star at 0.012 AU, about one-hundredth of the distance between the Earth and the Sun. It also completes a full revolution every fourteen hours.
“Mercury differs from other telluric planets in the solar system, containing a very large fraction of iron. It has therefore formed differently from others. We were surprised to see an exoplanet with the same high density, showing that the Mercury-type planets may not be as rare as we thought,” said British astronomer David Armstrong, lead author of this study. “Curiously, K2-229b is also the innermost planet in a system of at least 3 planets, although the three orbits are much closer to their star than the Sun’s Mercury.”
The dense, metallic nature of K2-229b could have many potential origins. One of the hypotheses suggests that its atmosphere may have been eroded by the winds and eruptions of its parent star. Stripped of its atmosphere, there would remain only a big hot and metallic ball. Another possibility is that K2-229b was formed as a result of a huge impact between two giant bodies in space billions of years ago – in the same way that the Moon would have formed after the Earth entered into collision with a body the size of Mars.