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Rare exoplanet 34 EP

GJ 338 B b

RA 138.5917° · Dec 52.6835° · exoplanet

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Score breakdown

· 4 badges
34 pts · Rare
Rare 50 pts → Epic
  • Nearby (<25 ly) +12
  • Two suns in its sky +12
  • Confirmed exoplanet +5
  • Sub-Neptune +5
Total score 34

16 more points to reach Epic.

Badges

  • Confirmed exoplanet · +5
  • Nearby (<25 ly) · +12
  • Sub-Neptune · +5
  • Two suns in its sky · +12

Trivia

What it actually is

  • Hugging its star. It orbits closer to its star than Mercury does to the Sun, completing a lap in less time than Mercury takes.
  • What it is made of. Too light to be solid rock and too heavy to be all gas: most likely a deep global ocean or a thick steamy envelope over a rocky core.

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 7.7 it is just past naked-eye reach — ordinary binoculars will pull it in.
  • Northern sky. It rides the northern half of the sky — an easier target the further north you are.
  • Best time of year. It stands highest in the middle of the night around February — that's when to go looking.

Could we get there?

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

Getting there

  • Aboard Voyager 1. ≈ 362.9 thousand years at Voyager 1's speed (17 km/s).

Properties

density gcc
1.7
diameter km
41457.65
discovery facility
Calar Alto Observatory
discovery method
Radial Velocity
discovery year
2020
dist ly
20.654
eccentricity
0.109
eq temp k
391
host star teff
4014
insolation
3.9278
mag
7.7
mass earth
10.6
multi star system
yes
name
GJ 338 B b
orbital period days
24.422
radius earth
3.25
semi major au
0.142
spect
M0 V
sys num planets
1
sys num stars
2

About GJ 338 B b

GJ 338 B b is a rare exoplanet. It lies about 20.7 light-years from Earth, shines at apparent magnitude 7.7, has spectral type M0 V and has an equilibrium temperature near 391 K.

It orbits closer to its star than Mercury does to the Sun, completing a lap in less time than Mercury takes.

How to see it

At apparent magnitude 7.7, it is an easy target for binoculars.

Like any astronomical target, GJ 338 B 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 338 B b is a rare exoplanet

GJ 338 B b scores 34 points on Spacedle's rarity scale, which places it in the rare tier. Another 16 points would lift it into a rarer tier.

That score comes from 4 science badges — Confirmed exoplanet, Nearby (<25 ly), Sub-Neptune and Two suns in its sky — 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.