Super-Earth HD 20794 d: A Near-Neighbor in the ‘Goldilocks’ Zone
Short version: In early 2025, scientists confirmed a new planet called HD 20794 d. Roughly 20 light-years from us, it orbits a Sun-like star and spends most of its long, elliptical path in the habitable zone, where liquid water could persist. That makes it a strong target for future life-searching missions.
What was found — in simple words
The planet: HD 20794 d is a super-Earth — bigger than Earth but much smaller than gas giants. Its mass is roughly six times Earth’s.
The neighborhood: It circles a nearby star named HD 20794, also known as 82 Eridani. At only ~20 light-years away, it’s practically “next door” in cosmic terms.
The path: One “year” there is about 647 days, and the orbit is elliptical—more oval than circle. That means it moves in and out of the star’s habitable zone — sometimes warmer, sometimes cooler.
How did scientists confirm it?
Researchers combined 20+ years of very precise measurements from two super-steady instruments in Chile, HARPS and ESPRESSO. These tools don’t take pictures of the planet; instead, they watch tiny “wobbles” in the star’s light caused by the planet’s gravity — a technique called radial velocity. After carefully removing noise from the data, the team confirmed three planets in the system, with the outer one being HD 20794 d in the habitable zone.
Can people live there?
Not something we can say yet. “Habitable zone” the star distance where a planet could keep liquid water on its surface if it has the right kind of atmosphere.. Because the orbit is so eccentric, temperatures could swing from very hot to very cold over a year. Positive steps, though still short of a “human habitat” claim.
Why is this exciting?
Close and bright: At ~20 light-years, this system is close enough for future telescopes to study in detail.
Great test case: Missions being planned — like the Habitable Worlds Observatory (HWO), the Extremely Large Telescope (ELT), and the proposed LIFE mission — could try to read the planet’s atmosphere and look for biosignature gases. That’s how we’ll move from “maybe” to real answers.
The bottom line
HD 20794 d is real, nearby, and intriguing. It’s a super-Earth that sometimes sits in the comfy zone for liquid water. We still need to learn whether it has an atmosphere and stable conditions, but it’s one of the best-placed targets for the next generation of life-search tools. Think of it as a promising neighbor we’ve just properly met — and we’re getting ready to pay a closer visit with better instruments.