← Back to dex
Uncommon exoplanet 27 EP

HD 11506 c

RA 28.2107° · Dec -19.5074° · exoplanet

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

Computing the sky for your location…

Score breakdown

· 4 badges
27 pts · Uncommon
Uncommon 33 pts → Rare
  • Puffy low-density world +12
  • Multi-planet system +6
  • Confirmed exoplanet +5
  • Gas giant +4
Total score 27

6 more points to reach Rare.

Badges

  • Confirmed exoplanet · +5
  • Gas giant · +4
  • Puffy low-density world · +12
  • Multi-planet system · +6

Trivia

What makes it special

  • Cotton-candy planet. So low-density it would float on water.

Could we get there?

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

Getting there

  • Aboard Voyager 1. ≈ 2.9 million years at Voyager 1's speed (17 km/s).
  • Fastest probe ever. ≈ 261.1 thousand years even at the Parker Solar Probe's 192 km/s.
  • At 10% light speed. ≈ 1672 years in a starship at a tenth of light speed.
  • Distance. 167 light-years from Earth.

Look-back time

  • Look-back time. The light you'd see left around the year 1859.

Saying hello

  • Say hello. A radio message and its reply would take 334 years round-trip.

Standing on it

  • A year here. A full year lasts just 224 Earth days.

By the numbers

  • Size. About 14× the width of Earth.
  • Volume. About 2744 Earths could fit inside it.
  • Mass. Roughly 127× Earth's mass — about 0.4 Jupiters.
  • Your weight. You'd weigh about 0.6× your Earth weight standing here.
  • Density. Less dense than water — drop it in a big enough ocean and it would float.
  • Temperature. A scorching 101°C on average.

How we found it

  • Discovery. Found by W. M. Keck Observatory using the radial velocity method.

Cosmic context

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

Properties

density gcc
0.255
discovery facility
W. M. Keck Observatory
discovery method
Radial Velocity
dist ly
167.1908
eccentricity
0.228
eq temp k
374.44
insolation
3.6537
mass earth
127.1314
name
HD 11506 c
orbital period days
223.92
radius earth
14
sys num planets
3

About HD 11506 c

HD 11506 c is an uncommon exoplanet. It lies about 167.2 light-years from Earth, has an equilibrium temperature near 374 K, spans roughly 14 Earth radii and weighs about 127.13 Earth masses.

So low-density it would float on water.

How to see it

Like any astronomical target, HD 11506 c 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 11506 c is an uncommon exoplanet

HD 11506 c scores 27 points on Spacedle's rarity scale, which places it in the uncommon tier. Another 6 points would lift it into a rarer tier.

That score comes from 4 science badges — Confirmed exoplanet, Gas giant, Puffy low-density world and Multi-planet system — 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.