← Back to dex
Common exoplanet 17 EP

GJ 9773 b

RA 333.1502° · Dec 8.5503° · exoplanet

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

Computing the sky for your location…

Score breakdown

· 3 badges
17 pts · Common
Common 22 pts → Uncommon
  • Frozen world +8
  • Confirmed exoplanet +5
  • Gas giant +4
Total score 17

5 more points to reach Uncommon.

Badges

  • Confirmed exoplanet · +5
  • Gas giant · +4
  • Frozen world · +8

Trivia

What makes it special

  • Frozen world. A deep-frozen world, too far from its star's warmth for anything to stay liquid.

Hard to believe

  • It would float. It is less dense than water. Drop it in a big enough ocean and the whole world would bob on the surface.

What it actually is

  • What it is made of. Lighter than Neptune — a puffed-up ball of hydrogen and helium with no surface anywhere on it to stand on.

Sense of scale

  • In perspective. Inside our stellar backyard: every radio broadcast humanity has ever made has already swept past it.

Find it in the sky

  • How to spot it. At magnitude 12 it is far too faint for the eye: this one belongs to cameras and long exposures.
  • Seen from everywhere. It sits almost on the celestial equator, so it can be seen from essentially anywhere on Earth.
  • Best time of year. It stands highest in the middle of the night around August — that's when to go looking.

Could we get there?

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

Properties

density gcc
0.331
diameter km
181138.04
discovery facility
Calar Alto Observatory
discovery method
Radial Velocity
discovery year
2025
dist ly
51.9276
eccentricity
0.218
eq temp k
59.89
host star teff
3528
insolation
0.0021
mag
12.033
mass earth
172.5808
name
GJ 9773 b
orbital period days
2965
radius earth
14.2
semi major au
2.921
spect
M3.0 V
sys num planets
1
sys num stars
1

About GJ 9773 b

GJ 9773 b is a common exoplanet. It lies about 51.9 light-years from Earth, shines at apparent magnitude 12.03, has spectral type M3.0 V and has an equilibrium temperature near 60 K.

A deep-frozen world, too far from its star's warmth for anything to stay liquid.

How to see it

At apparent magnitude 12.03, it takes a larger telescope or a long-exposure image to capture.

Like any astronomical target, GJ 9773 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 GJ 9773 b is a common exoplanet

GJ 9773 b scores 17 points on Spacedle's rarity scale, which places it in the common tier. Another 5 points would lift it into a rarer tier.

That score comes from 3 science badges — Confirmed exoplanet, Gas giant and Frozen world — 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.