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Rare exoplanet 39 EP

HD 224538 b

RA 359.7164° · Dec -61.5869° · exoplanet

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Score breakdown

· 3 badges
39 pts · Rare
Rare 46 pts → Epic
  • In the habitable zone +30
  • Confirmed exoplanet +5
  • Gas giant +4
Total score 39

7 more points to reach Epic.

Badges

  • Confirmed exoplanet · +5
  • In the habitable zone · +30
  • Gas giant · +4

Trivia

What makes it special

  • Goldilocks zone. Sits where it's neither too hot nor too cold — liquid water could exist.

Could we get there?

  • Verdict. Hopelessly far for any craft humanity can build today.

Getting there

  • Aboard Voyager 1. ≈ 4.5 million years at Voyager 1's speed (17 km/s).
  • Fastest probe ever. ≈ 402.6 thousand years even at the Parker Solar Probe's 192 km/s.
  • At 10% light speed. ≈ 2579 years in a starship at a tenth of light speed.
  • Distance. 258 light-years from Earth.

Look-back time

  • Look-back time. The light you'd see left around the year 1768.

Saying hello

  • Say hello. A radio message and its reply would take 516 years round-trip.

Standing on it

  • A year here. A full year lasts about 3.3 Earth years.

By the numbers

  • Size. About 12.7× the width of Earth.
  • Volume. About 2048 Earths could fit inside it.
  • Mass. Roughly 2076× Earth's mass — about 6.5 Jupiters.
  • Your weight. You'd weigh about 12.9× your Earth weight standing here.
  • Temperature. A frigid -36°C — colder than dry ice.

How we found it

  • Discovery. Found by Multiple Observatories using the radial velocity method.

Properties

density gcc
5.57
discovery facility
Multiple Observatories
discovery method
Radial Velocity
dist ly
257.8615
eccentricity
0.476
eq temp k
236.74
habitable zone
yes
insolation
0.523
mass earth
2075.7373
name
HD 224538 b
orbital period days
1202.052
radius earth
12.7
sys num planets
1

About HD 224538 b

HD 224538 b is a rare exoplanet. It lies about 257.9 light-years from Earth, has an equilibrium temperature near 237 K, spans roughly 12.7 Earth radii and weighs about 2,075.74 Earth masses.

Sits where it's neither too hot nor too cold — liquid water could exist.

How to see it

Like any astronomical target, HD 224538 b is best seen from a dark site away from city lights, and when it is above the horizon depends on your latitude and the time of year. The visibility panel above works out tonight's viewing window for your saved location.

Why HD 224538 b is a rare exoplanet

HD 224538 b scores 39 points on Spacedle's rarity scale, which places it in the rare tier. Another 7 points would lift it into a rarer tier.

That score comes from 3 science badges — Confirmed exoplanet, In the habitable zone and Gas giant — each earned for a real, measurable property of the object. Rarity on Spacedle is never random: the more remarkable an object's astrophysics, the more badges it collects, the higher it scores, and the rarer it ranks.

spacedle A daily roll through the real universe. © 2026 spacedle. Buy me a coffee

Sky imagery and survey data courtesy of Aladin Lite & CDS, Strasbourg. Object data from the NASA Exoplanet Archive, JPL Small-Body Database, and the ATNF Pulsar Catalogue.