Presentation of the Tui-566 by the artist, the oldest, most metallic-poor planetary system ever discovered in the Milky Way galaxy. WM Cake Observatory / Adam Makarenko
Researchers have identified one of the oldest planetary systems discovered so far and this is an amazing one. A rocky planet called TOI-561b orbits a star 10 million years old, which shows that the planets were formed from the earliest times of the universe, more than twice as long as our Sun.
The planet, which is about 1.5 times the size of Earth and is therefore called Super-Earth, orbits its star in one Earth day. It whips around its star so quickly because it is so close to it, which means the planet has a dramatically higher surface temperature of more than 1,700 degrees Celsius.
Super-fast years and high temperatures are not the only notable features of this exotic peculiarity. The planet also has an unusually low density for its size, although it is about three times the mass of Earth, it has the same density as our planet. This suggests that it is very old, according to the authors of the study.
Older planets are less dense because they have less heavy elements like metals. These heavy elements are formed between the stars as they get bigger and eventually explode into a supernova and the elements are distributed in the spaces around them from which the planets are formed. Earlier in the universe, fewer stars exploded and so the planets formed with less heavy material in them.
“Toi-561B is one of the oldest rocky planets ever found,” Lauren Weiss, a postdoctoral fellow at the University of Hawaii and team leader, said in a statement. “Its existence shows that the universe has been forming rocky planets since its inception about 1400 billion years ago.”
The team identified the planet using NASA’s Transiting Exoplanet Survey Satellite or TSES and confirmed its presence using the WM Cake Observatory in Hawaii.
Stephen Lane, lead author of the study at the University of California, Riverside, said the discoveries could be just the beginning of many more rocky planets around the old star to be discovered on upcoming missions.
“While this particular planet is unlikely to exist today, it may still be home to many rocky Earths in the vicinity of the oldest stars in our galaxy.”
The study was presented at the 2021 meeting of the American Astronomical Society and will be published in the Astronomical Journal.