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Common exoplanet 17 EP

GJ 9773 b

RA 333.1502° · Dec 8.5503° · exoplanet

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Score breakdown

· 3 badges
17 pts · Common
Common 24 pts → Uncommon
  • Frozen world +8
  • Confirmed exoplanet +5
  • Gas giant +4
Total score 17

7 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 far from its star's warmth.

Could we get there?

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

Getting there

  • Aboard Voyager 1. ≈ 912.5 thousand years at Voyager 1's speed (17 km/s).
  • Fastest probe ever. ≈ 81.1 thousand years even at the Parker Solar Probe's 192 km/s.
  • At 10% light speed. ≈ 519 years in a starship at a tenth of light speed.
  • Distance. 51.9 light-years from Earth.

Look-back time

  • Look-back time. The light you'd see left around the year 1974.

Saying hello

  • Say hello. A radio message and its reply would take 104 years round-trip.

Standing on it

  • A year here. A full year lasts about 8.1 Earth years.

By the numbers

  • Size. About 14.2× the width of Earth.
  • Volume. About 2863 Earths could fit inside it.
  • Mass. Roughly 173× Earth's mass — about 0.5 Jupiters.
  • Your weight. You'd weigh about 0.9× your Earth weight standing here.
  • Density. Less dense than water — drop it in a big enough ocean and it would float.
  • Temperature. A frigid -213°C — colder than dry ice.

How we found it

  • Discovery. Found by Calar Alto Observatory using the radial velocity method.

Properties

density gcc
0.331
discovery facility
Calar Alto Observatory
discovery method
Radial Velocity
dist ly
51.9276
eccentricity
0.218
eq temp k
59.89
insolation
0.0021
mass earth
172.5808
name
GJ 9773 b
orbital period days
2965
radius earth
14.2
sys num planets
1

About GJ 9773 b

GJ 9773 b is a common exoplanet. It lies about 51.9 light-years from Earth, has an equilibrium temperature near 60 K, spans roughly 14.2 Earth radii and weighs about 172.58 Earth masses.

A deep-frozen world far from its star's warmth.

How to see it

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 7 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.

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.