Astronomers have found a new Super-Earth planet that’s nearly as old as the universe itself, but despite what the name might indicate, the words “Super-Earth” only speak to the exoplanet’s size as this new planet doesn’t have many similarities to Earth.
This new Super-Earth is called TOI-561b and it’s 50% larger than Earth, according to UC Riverside News. It orbits its star in less than half a day though, despite how much larger it is than Earth, which orbits its star, the Sun, every 365 days. TOI-561b is, all things considered, quite different from Earth, but the reason it’s called a Super-Earth is almost exclusively because of its size.
“Super-Earths — a class of planets unlike any in our solar system — are more massive than Earth yet lighter than ice giants like Neptune and Uranus, and can be made of gas, rock, or a combination of both,” according to NASA’s official definition of a Super-Earth.
“They are between twice the size of Earth and up to 10 times its mass. Super-Earth is a reference only to an exoplanet’s size — larger than Earth and smaller than Neptune — but not suggesting they are necessarily similar to our home planet.”UC Riverside planetary astrophysicist, Stephen Kane, said that for every day we spend on Earth, TOI-561b orbits its star twice. The reason for this quick orbit is due to the heat created by the planet’s close proximity to the star it orbits. TOI-561b’s temperature is over 2000 degrees Kelvin, which is obviously too hot for life as we know it to exist on the planet. The other reason for the speedy orbit is due to the planet’s density, which is roughly the same as Earth’s.
“This is surprising because you’d expect the density to be higher,” Kane said. “This is consistent with the notion that the planet is extremely old.”
The older a planet is, the less dense it generally is and that’s because the materials that make a planet dense simply weren’t as abundant the farther back in time you go. The materials that eventually form dense planets are heavy elements that are produced by fusion reactions in stars as they age, according to UC Riverside News. When stars explode, the elements are scattered outward and those elements form new stars and new planets.
Because TOI-561b is not nearly as dense as expected, the astronomers that discovered the Super-Earth believe it to be as old as the universe itself as at that point in time, heavy elements to create a more dense planet would not have been as readily available as fewer stars were exploding since they weren’t as old.