Scientists have located a “Super Earth” that is believed to orbit one of the oldest stars in the Milky Way galaxy. The exoplanet gets its title because it is suspected to be about three times the mass of Earth, with a size 50% larger than our home planet.
The planet, known as TOI-561b, has been described in a new study accepted for publication in The Astronomical Journal. Despite the planet’s mass, its density is about the same as that of Earth, astronomers in the study found.
“We report the discovery of TOI-561, a multi-planet system in the thick galactic disk that contains a rocky, ultra-short-lived planet (USP),” the study said.
The planet gets its name from NASA’s Transiting Exoplanet Survey Satellite (TESS) in 2018. The “TOI” in TOI-561b means TESS. It is located outside the solar system, in the thick galactic disk of the Milky Way, explains a CNN report. Due to the proximity of the host star, it takes less than half a day on Earth to complete an orbit around it.
“For every day you are on Earth, this planet orbits its star twice,” Stephen Kane, co-author of the study and astrophysicist at the University of California, Riverside, said in a statement. The researchers determined the mass, radius and density of the planet using the WM Keck Observatory in Hawaii.
(Representative image: Reuters)
This approach to the “super-Earth” results in an average surface temperature on the planet that exceeds 2,000 Kelvin or 3,140 degrees Fahrenheit. TOI-561b is therefore too hot to be habitable. Although astronomers know that the rocky planet and its star form a 10 billion-year-old system, they wonder if the planet has sheltered life at some point in its past.
“TOI-561b is one of the oldest rocky planets ever discovered,” study lead author Lauren Weiss said in a statement. “Its existence shows that the universe has formed rocky planets close to its creation 14 billion years ago.” In comparison, our sun is only 4.5 billion years old.
Such older planets turn out to be less dense than the more recently formed planets. This is because there were not as many heavy elements present in the universe at that time. Such elements were eventually created by stars that met in a supernova.
The study highlights two other planets orbiting the star, both of which are probably gaseous and larger than TOI-561b.