← Back to dex
Rare exoplanet 37 EP

Kepler-126 d

RA 289.3474° · Dec 44.2084° · exoplanet

Loading sky survey…
🌌 View in 3D star map
Tonight’s visibility

Computing the sky for your location…

Score breakdown

· 5 badges
37 pts · Rare
Rare 46 pts → Epic
  • Denser than iron +18
  • Multi-planet system +6
  • Confirmed exoplanet +5
  • Sub-Neptune +5
  • Found by Kepler +3
Total score 37

9 more points to reach Epic.

Badges

  • Confirmed exoplanet · +5
  • Sub-Neptune · +5
  • Denser than iron · +18
  • Multi-planet system · +6
  • Found by Kepler · +3

Trivia

What makes it special

  • Heavyweight. Packed denser than solid iron.

Could we get there?

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

Getting there

  • Aboard Voyager 1. ≈ 13.6 million years at Voyager 1's speed (17 km/s).
  • Fastest probe ever. ≈ 1.2 million years even at the Parker Solar Probe's 192 km/s.
  • At 10% light speed. ≈ 7743 years in a starship at a tenth of light speed.
  • Distance. 774 light-years from Earth.

Look-back time

  • Look-back time. The light you'd see left around the year 1252.

Saying hello

  • Say hello. A radio message and its reply would take 1549 years round-trip.

Standing on it

  • A year here. A full year lasts just 100 Earth days.

By the numbers

  • Size. About 2.5× the width of Earth.
  • Volume. About 15.6 Earths could fit inside it.
  • Mass. Roughly 54.6× Earth's mass — about 0.2 Jupiters.
  • Your weight. You'd weigh about 8.7× your Earth weight standing here.
  • Density. Denser than solid iron.
  • Temperature. A scorching 202°C on average.

How we found it

  • Discovery. Found by Kepler using the transit method.

Cosmic context

  • Crowded system. One of at least 3 planets orbiting its star.

Properties

density gcc
18.3989
discovery facility
Kepler
discovery method
Transit
dist ly
774.2976
eccentricity
0.02
eq temp k
475
insolation
14.714
mass earth
54.5902
name
Kepler-126 d
orbital period days
100.2831
radius earth
2.5
sys num planets
3

About Kepler-126 d

Kepler-126 d is a rare exoplanet. It lies about 774.3 light-years from Earth, has an equilibrium temperature near 475 K, spans roughly 2.5 Earth radii and weighs about 54.59 Earth masses.

Packed denser than solid iron.

How to see it

Like any astronomical target, Kepler-126 d 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 Kepler-126 d is a rare exoplanet

Kepler-126 d scores 37 points on Spacedle's rarity scale, which places it in the rare tier. Another 9 points would lift it into a rarer tier.

That score comes from 5 science badges — Confirmed exoplanet, Sub-Neptune, Denser than iron, Multi-planet system and Found by Kepler — 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.