About Kepler-51 d
Kepler-51 d is a rare exoplanet. It lies about 2,556.5 light-years from Earth, has an equilibrium temperature near 381 K, spans roughly 9.7 Earth radii and weighs about 7.6 Earth masses.
So low-density it would float on water.
Rare exoplanet 40 EP
Kepler-51 d
RA 296.4798° · Dec 49.9376° · exoplanet
Score breakdown
· 6 badgesRare 46 pts → Epic
- Puffy low-density world +12
- Distant (>1000 ly) +10
- Multi-planet system +6
- Confirmed exoplanet +5
- Gas giant +4
- Found by Kepler +3
Total score 40
6 more points to reach Epic.
Badges
- Confirmed exoplanet · +5
- Gas giant · +4
- Puffy low-density world · +12
- Multi-planet system · +6
- Found by Kepler · +3
- Distant (>1000 ly) · +10
Trivia
What makes it special
- Cotton-candy planet. So low-density it would float on water.
Could we get there?
- Verdict. Impossible with our current technology — and the next millennium of it.
Getting there
- Aboard Voyager 1. ≈ 44.9 million years at Voyager 1's speed (17 km/s).
- Fastest probe ever. ≈ 4 million years even at the Parker Solar Probe's 192 km/s.
- At 10% light speed. ≈ 25.6 thousand years in a starship at a tenth of light speed.
- Distance. 2557 light-years from Earth.
Look-back time
- Look-back time. Its light left before the last ice age ended.
Saying hello
- Say hello. A radio message and its reply would take 5113 years round-trip.
Standing on it
- A year here. A full year lasts just 130 Earth days.
By the numbers
- Size. About 9.7× the width of Earth.
- Volume. About 913 Earths could fit inside it.
- Mass. About 7.6× the mass of Earth.
- Your weight. You'd weigh about 0.1× your Earth weight standing here.
- Density. Less dense than water — drop it in a big enough ocean and it would float.
- Temperature. A scorching 108°C on average.
How we found it
- Discovery. Found by Kepler using the transit method.
Cosmic context
- Crowded system. One of at least 4 planets orbiting its star.
Properties
- density gcc
- 0.046
- discovery facility
- Kepler
- discovery method
- Transit
- dist ly
- 2556.5118
- eccentricity
- 0.008
- eq temp k
- 381
- insolation
- 2.466
- mass earth
- 7.6
- name
- Kepler-51 d
- orbital period days
- 130.194
- radius earth
- 9.7
- sys num planets
- 4
How to see it
Like any astronomical target, Kepler-51 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-51 d is a rare exoplanet
Kepler-51 d scores 40 points on Spacedle's rarity scale, which places it in the rare tier. Another 6 points would lift it into a rarer tier.
That score comes from 6 science badges — Confirmed exoplanet, Gas giant, Puffy low-density world, Multi-planet system, Found by Kepler and Distant (>1000 ly) — 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.