'Super-Earth' Exoplanet Discovered Orbiting One Of The Oldest Stars In The Milky Way

Scientists have located a ¡®Super Earth¡¯ that is being believed to orbit one of the oldest stars in the Milky Way galaxy. The exoplanet gets its title as it is suspected to be around 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 The Astronomical Journal. Despite the planet's mass, its density is about the same as that of Earth, astronomers found in the study.

¡°We report the discovery of TOI-561, a multi-planet system in the galactic thick disk that contains a rocky, ultra-short period planet (USP),¡± the study mentions.

The planet gets its name from the planet-hunting Transiting Exoplanet Survey Satellite (TESS) mission conducted by NASA in 2018. The "TOI" in TOI-561b stands for TESS Object of Interest. It is located outside the solar system, in the thick galactic disk of the Milky Way, explains a report by CNN. Due to its proximity to the host star, it only takes less than half Earth day to complete one orbit around it.

"For every day you're on Earth, this planet orbits its star twice," said Stephen Kane, study co-author and astrophysicist at the University of California, Riverside, in a statement. The researchers determined the planet's mass, radius and density using the W.M. Keck Observatory in Hawaii.

(Representative Image: Reuters)

This close proximity of the ¡®super-Earth' results in the average surface temperature on the planet exceeding 2,000 Kelvin, or 3,140 degrees Fahrenheit. TOI-561b is, hence, too hot to be habitable. Though since astronomers know that the rocky planet and its star form a 10 billion years old system, they wonder if the planet harboured life at any point in its past.

"TOI-561b is one of the oldest rocky planets yet discovered," said lead study author Lauren Weiss in a statement. "Its existence shows that the universe has been forming rocky planets almost since its inception 14 billion years ago." In comparison, our sun is only 4.5 billion years old.

Such older planets are found to be less dense than the more recently formed planets. This is because there weren't as many heavy elements present in the universe at the time. Such elements have been created eventually by stars who met their end in a supernova.

The study highlights two other planets orbiting the star, which are both likely gaseous and larger than TOI-561b.