Unbelievably Hot, Earth-Sized And Tidally Locked Planet With A ‘Lava Hemisphere’ – Discovered

Eddie Gonzales Jr. – MessageToEagle.com – A small celestial body – extra hot, Earth-sized, and transiting across the sun-sized star  – was recently spotted in Ursa Major’s constellation.

The discovered exoplanet named HD 63433 d is fascinating because it exhibits a unique characteristic known as tidal locking. It means that the planet’s one side always faces its star while the other remains shrouded in darkness.

Like Kepler-10 b, illustrated above, the exoplanet HD 63433 d is a small, rocky planet in a tight orbit of its star. HD 63433 d is the smallest confirmed exoplanet younger than 500 million years old. It’s also the closest discovered Earth-sized planet this young, at about 400 million years old. NASA/Ames/JPL-Caltech/T. Pyle

The HD 63433 resides outside our solar system and orbits the star HD 63433 (TOI 1726).

Interestingly, this extremely hot world holds, for now, the record for being the smallest confirmed exoplanet that’s less than 500 million years old. Additionally, at approximately 400 million years old, it’s also recognized as the nearest Earth-sized planet of its age ever discovered.

To analyze this planetary system, astronomers used data from NASA’s TESS (Transiting Exoplanet Survey Satellite), which spots “transits,” or instances where planets cross in front of their star as they orbit, blocking a tiny piece of the starlight.

Two planets had already been previously discovered in this planetary system, so to see what else might be lurking in the star’s orbit, the team took the data and removed the signals of the two known planets. This allowed them to see an additional signal – a small transit reappearing every 4.2 days. Further investigation confirmed that this was actually a third, smaller planet.

This planet that’s always showing the same face to its star is pretty much like Earth (about 1.1 times our planet’s diameter.) It’s circling around a star that could be our sun’s twin, being roughly 0.91 the size and almost identical in mass!

And yet, the planet HD 63433 d is quite different from our home world.

Young, hot, Earth-sized planet HD 63433d sits close to its star in the constellation Ursa Major, while two neighboring, mini-Neptune-sized planets — identified in 2020 — orbit farther out.
Credit: Alyssa Jankowski

To begin with, this planet is remarkably young, situated in a system that is considerably younger than ours. The age of the planetary system is about one-tenth of ours, making this 400-million-year-old planet a mere infant compared to our 4.5-billion-year-old Earth.

Furthermore, its proximity to its star greatly surpasses ours. This planet’s distance from its star is eight times less than that between Mercury and the Sun. Due to such close quarters with its star, the dayside of this tidally locked planet can experience extreme temperatures reaching approximately 2,294 Fahrenheit (1,257 Celsius).

Considering intense heat due to proximity to its star and small size – it’s likely that this planet does not possess a substantial atmosphere.

The unbearable heat on this planet is akin to that of lava worlds such as CoRoT-7 b and Kepler-10 b.

The researchers behind this fascinating discovery speculate that one-half of the planet could be a “lava hemisphere.” Given its compact size, youthful age, and proximity to its star, this celestial body presents an intriguing subject for further investigation.

Further research may validate the findings of this study while potentially unveiling more about the planet’s “dark side” and the condition of its potential atmosphere. As stated in this study, young terrestrial planets are crucial for testing prevailing planetary theories.

Paper

Written by Eddie Gonzales  Jr. – MessageToEagle.com Staff Writer