‘Super-Earth’ exoplanet revolves around one of the oldest stars in the Milky Way

Scientists have located a ‘super earth’, which is believed to be one of the oldest stars in the Milky Way galaxy. Exoplanet gets its title because it is suspected to be about three times the mass of Earth, 50% larger than its home planet.

The planet, known as TOI-561b, is described in a new study accepted for publication in The Astronomical Journal. Despite the planet’s mass, its density is similar to that of the Earth, astronomers found in the study.

“We report the discovery of TOI-561, a multi-planetary system in a galactic thick disk consisting of a rocky, ultra-short-term 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. “TOI” in TOI-561b means TESS of interest. It is located outside the solar system in a thick galactic disk of the Milky Way, according to a CNN report. Due to its proximity to the host star, it takes only less than half Earth Day to complete an orbit around it.

“For every day you are on Earth, this planet orbits its star twice,” Stephen Kane co-authored and astrophysicist at the University of California, Riverside, in a statement. Researchers determined the planet’s mass, radius, and density using the WM KK Observatory in Hawaii.

(Representative image: Reuters)

This proximity to ‘super-earth’ resulted in average surface temperatures on the planet exceeding 2,000 Kelvin or 3,140 degrees Fahrenheit. The TOI-561b is, therefore, too hot to be habitable. Although astronomers know that the rocky planet and its star are a 10 billion year old system, they wonder if the planet disturbed 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 suggests that the universe has been forming rocky planets since its inception nearly 14 billion years ago.” In comparison, our Sun is only 4.5 billion years old.

Such old planets are found to be less dense than recently formed planets. This is because there were no such heavy elements present in the universe at that time. Such elements are ultimately created by the stars who met their end in a supernova.

The study also highlights the orbit of two other planets, which are both gaseous and larger than the TOI-561b.


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