Astronomers discover Earth-sized scorching world with lava hemisphere

Astronomers have spotted a new Earth-sized hot scorching world transiting across the Sun-sized star in a system with two known planets. The newly discovered exoplanet, called HD 63433 d, orbits around the star HD 63433 (TOI 1726) in the HD 63433 planetary system and is the smallest confirmed exoplanet younger than 500 million years old

HD 63433 d is also the closest discovered Earth-sized planet this young, at about 400 million years old.

The planetary system was examined using data collected by NASA's TESS (Transiting Exoplanet Survey Satellite). Two planets had already been discovered in this system, so to explore what else might be present in the star's orbit, the team analyzed the data and eliminated the signals of the two known planets. This helped them identify an additional signal and following further investigations, they were able to confirm that this was indeed a third, smaller planet.

The planet HD 63433 d, which is tidally locked orbits a G-type star, is comparable to the size of our sun. The planet is approximately 1.1 times the diameter of our Earth.

Despite these similarities, HD 63433 d is quite different from our Earth. Firstly, it is a very young planet (400 million years old) in a very young system, about 10 times younger than ours. The planet orbits much closer to its star than we do, which results in a year that lasts only 4.2 days, and experiences extremely high temperatures on its dayside.

The scorching temperatures are comparable to lava worlds like CoRoT-7 b and Kepler-10 b, and the team behind this discovery believes that the planet's dayside may be a "lava hemisphere." Due to its close proximity to its star, young age, and small size, the planet is a fascinating subject for further exploration.

📣 Discovery Alert! 📣 An Earth-sized exoplanet with a lava hemisphere! HD 63433 d is in a system with two previously known worlds. A ''year'' there, one orbit of its star, takes 4.2 days. https://t.co/8j8OtbkMRo pic.twitter.com/c00oOTFCr6

— NASA Exoplanets (@NASAExoplanets) January 10, 2024