Scientists have discovered a new exoplanet that is Earth-sized and is just as dense as Mercury. This new discovery can inform scientists on how the planet Mercury — and other unusually dense planets — form.
This is the most dense Earth-sized planet discovered so far.
Hot And Metallic
Researchers from the University of Warwick and Aix-Marseille University published a paper in Nature Astronomy detailing the discovery of the new exoplanet. They found that the planet K2-229b has a mass that is around 2.6 times the mass of Earth. It is the first time that scientists have been able to measure the mass of the planet.
K2-229b is almost 20 percent larger than the Earth. It's surface dayside temperature is over 2,000 degrees Celsius. It is also very close to its host star at only 0.012 AU (1,115,469.7 miles) away. This is compared to Mercury, which is 0.4 AU (35,000,000 miles) away from the Sun. It orbits a K-dwarf star that is bright.
The planet was discovered using the K2 telescope. In order to identify the planet, researchers used Doppler spectroscopy, which is also known as the wobble method. This method works by scientists observing the slight shift in a star when it is being affected by the gravitational pull of the planet that orbits it.
Scientists used this wobble method to calculate the size, position, and mass of the planet.
Formation Of Mercury
Scientists were stunned to see that the planet had the same high density as Mercury. This could show that Mercury-type planets are more common than they are once perceived. Just like Mercury, K2-229b is the innermost planet in its system that could shed light on how Mercury was formed.
Researchers have come up with theories on how K2-229b formed in the study. One of the theories is that due to its proximity to its host star, intense stellar winds and flares have eroded the planet's atmosphere. The only problem with this theory is that the researchers aren't sure whether K2-229b has its own magnetic field protecting it from such conditions.
Another theory proposed by the scientists is that a similar planet hit the original planet, and this sent the material flying away. This material could have led to the formation of a moon.
The team's last theory is that the K2-229b is made up of the same material as its host star. It formed as a dense metallic planet because those were the materials that were available at the time of its formation.