Earth-sized planet discovered in ‘our solar backyard’

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. Illustration: Alyssa Jankowski

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. Illustration: Alyssa Jankowski

A team of astronomers have discovered a planet closer and younger than any other Earth-sized world yet identified. It’s a remarkably hot world whose proximity to our own planet and to a star like our sun mark it as a unique opportunity to study how planets evolve.

The new planet was described in a new study published this week by The Astronomical Journal. Melinda Soares-Furtado, a NASA Hubble Fellow at the University of Wisconsin–Madison who will begin work as an astronomy professor at the university in the fall, and recent UW–Madison graduate Benjamin Capistrant, now a graduate student at the University of Florida, co-led the study with co-authors from around the world.

“It’s a useful planet because it may be like an early Earth,” says Soares-Furtado.

Here is what scientists know about the planet…