Researchers have identified what they say is one of the oldest planetary systems that has ever been discovered. The planetary system has a rocky planet known as TOI-561b orbiting a star that is 10 billion years old. That star is more than twice as old as the sun, and researchers say it shows planets have been forming since the early days of the universe.
TOI-561b is about 1.5 times the size of Earth, making it a Super-Earth. One of the most interesting aspects of the planet is that it has an extremely fast orbit circling its star more than twice in a single Earth day. It orbits so quickly because it’s very close to the host star.
The odds of the Super-Earth being habitable are slim. It’s believed to have a surface temperature of over 1700 degrees Celsius. Another interesting aspect of the planet is that it has an unusually low density for its size. While it’s about three times the mass of Earth, it has the same density as our planet. Scientists say that suggests TOI-561b is very old.
Older planets are less dense due to having fewer heavy elements such as metals. Heavy elements are created within stars as they get older and explode into a supernova. The supernova explosion distributes elements into space around them, and planets incorporate those elements when they form. In the early universe, fewer star explosions had occurred, and the result was planets forming with less heavy elements inside.
TOI-561b on the oldest rocky planets ever discovered. Researcher Lauren Weiss said that the existence of TOI-561b proves rocky planets have been forming almost since the beginning of the universe 14 billion years ago. The planet was discovered using data from NASA’s TESS mission and confirmed using the W.M. Keck Observatory in Hawaii.