Using NASA’s Transiting Exoplanet Survey Satellite (TESS), astronomers have noticed an Earth-sized planet transiting the younger Sun-like star HD 63433.

HD 63433d sits near its mother or father star, HD 63433, whereas two neighboring, mini-Neptune-sized planets, HD 63433b and HD 63433c, orbit farther out. Image credit score: Alyssa Jankowski.

HD 63433 is a G5V-type star positioned roughly 73 light-years away within the constellation of Gemini.

Otherwise referred to as TOI-1726, the star is a member of the 414-million-year-old Ursa Major transferring group of stars.

The newly-discovered exoplanet, HD 63433d, is the third planet detected on this multiplanet system.

The discovery of the opposite two planets — HD 63433b and HD 63433c, each mini Neptunes — was reported by astronomers in 2020.

HD 63433d is tidally locked, which means there’s a dayside which all the time faces its star and a facet that’s always in darkness.

The planet has an orbital interval of 4.2 days and intensely excessive temperatures (1,257 levels Celsius, or 2,294 levels Fahrenheit) on its dayside.

“These scorching temperatures are comparable to lava worlds like CoRoT-7b and Kepler-10b, and we think that the planet’s dayside could be a ‘lava hemisphere’,” stated University of Florida astronomer Benjamin Capistrant and his colleagues.

HD 63433d is the smallest confirmed exoplanet youthful than 500 million years outdated.

It’s additionally the closest found Earth-sized exoplanet this younger.

“HD 63433d is the closest planet to our Solar System with an Earth-like radius orbiting a young star,” the astronomers stated.

“Therefore, this is an appealing target for follow-up observations, offering an opportunity to reveal insights into the physics of exoplanet atmospheric mass loss.”

“Between HD 63433d and the two previously known larger planets, the HD 63433 system is poised to play an important role in our understanding of planetary system evolution in the first billion years after formation.”

The discovery of HD 63433d is reported in a paper within the Astronomical Journal.

_____

Benjamin Ok. Capistrant et al. 2024. TESS Hunt for Young and Maturing Exoplanets (THYME). XI. An Earth-sized Planet Orbiting a Nearby, Solar-like Host within the 400 Myr Ursa Major Moving Group. AJ 167, 54; doi: 10.3847/1538-3881/ad1039