In a system with two known planets, astronomers have found a new, Earth-sized, scorching planet transiting across the star the size of the Sun. The newest verified exoplanet under 500 million years old, HD 63433 d, is located in the HD 63433 planetary system and revolves around the star HD 63433 (TOI 1726).
With an estimated age of 400 million years, HD 63433 d is also the youngest Earth-sized planet ever found.
To study the planetary system, researchers used data from NASA’s TESS (Transiting Exoplanet Survey Satellite). As there were already two planets found in this system, the researchers studied the data and removed the signals from the two known planets to see what else might be in the star’s orbit. This enabled them to recognize a second signal, and after conducting more research, they were able to verify that this was, in fact, a third, smaller planet.
The tidally locked planet HD 63433 d is similar in size to our sun and orbits a G-type star. The planet’s diameter is roughly 1.1 times that of Earth.
Even with these parallels, HD 63433 d differs greatly from Earth. First off, at 400 million years old, the planet is within a relatively young system—roughly ten times younger than our own. The planet’s year only lasts 4.2 days because it orbits its star far closer than ours does, and its dayside endures extraordinarily high temperatures.
Based on the comparison of the extreme temperatures to lava worlds such as CoRoT-7 b and Kepler-10 b, the discovery team suggests that the planet’s dayside could be a “lava hemisphere.” Owing to its small size, youthful age, and near proximity to its star, the planet is an intriguing topic for additional research.
📣 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
