A hot, metallic, Earth-sized planet with a density similar to Mercury -- situated 260 million light years away- - has been detected and characterized by a global team of astronomers, including the University of Warwick
• Hot, metallic, Earth-sized planet with a density similar to Mercury detected 260 million light years away and characterised by global team of astronomers, including the University of Warwick
• K2-229b is 20% larger than Earth but has a mass 2.6 times greater - and a dayside temperature of over 2000°C
• Discovering details about far-flung planets across the universe gives us more clues as to how planets in our own solar system formed

A hot, metallic, Earth-sized planet with a density similar to Mercury - situated 260 million light years away -- has been detected and characterised by a global team of astronomers, including the University of Warwick. Dr. David Armstrong from the University of Warwick's Astronomy and Astrophysics Group, commented:

"Mercury stands out from the other Solar System terrestrial planets, showing a very high fraction of iron and implying it formed in a different way. Explore further 'Monster' planet discovery challenges formation theory

More information: An Earth-sized exoplanet with a Mercury-like composition, Nature Astronomy, nature.com/articles/doi:10.1038/s41550-018-0420-5 Journal information: Nature Astronomy An Earth-sized exoplanet with a Mercury-like composition, Named K2-229b, the planet is almost 20 percent larger than Earth but has a mass which is over two-and-a-half times greater—and reaches a dayside temperature of over 2000°C (2330 Kelvin). The planet is located eerily close to its star, approximately a hundredth of the distance between Earth and sun, and makes one hell of a place to live where daytime temperatures going way beyond 2000°C. Using the K2 telescope, researchers from Aix-Marseille Universite in France and University of Warwick in the UK employed the Doppler spectroscopy technique – also known as the ‘wobble method’ – to discover and characterise this faraway planet. The astronomers knew the planet was there due to dips in the light from its host star as it orbited, periodically blocking starlight. "Interestingly K2-229b is also the innermost planet in a system of at least 3 planets, though all three orbit much closer to their star than Mercury," Armstrong said. Astronomers believe that the new discovery can help explain what happened to Mercury and how the rocky planets in the Solar System were formed. The first relies on the closeness between the planet and its star and suggests intense solar winds and flares might have evaporated its atmosphere, while the second hints at a more chaotic past where a collision between two massive astronomical bodies would have led to the formation of the planet. Credit: University of Warwick

Another possibility is that K2-229b was formed after a huge impact between two giant astronomical bodies in space billions of years ago—much like the theory that the Moon was formed after Earth collided with a body the size of Mars. To date, they have found more than 20 supernovae using data from the Kepler spacecraft, including an exotic type reported by Rest in a new study in Nature Astronomy.
Led overall by researchers at Aix-Marseille Université in France using NASA's Kepler Space Telescope, Nature Astronomy publishes observations of what may be a new exoplanet named K2-229b, whose attributes may resemble the planet of Mercury (hot, metallic, and dense).