← Back to dex
Uncommon exoplanet 27 EP

GJ 238 b

RA 98.4549° · Dec -58.5250° · 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 34 pts → Rare
  • Tidally locked +10
  • Orbits a red dwarf +8
  • Confirmed exoplanet +5
  • Found by TESS +4
Total score 27

7 more points to reach Rare.

Badges

  • Confirmed exoplanet · +5
  • Tidally locked · +10
  • Found by TESS · +4
  • Orbits a red dwarf · +8

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. Its density says rock, though lighter than Earth's mix: probably less iron, or a thick shell of water and ice over the top.

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 11.6 you'll want a small backyard telescope.
  • Southern sky. It rides the southern half of the sky — an easier target the further south you are.
  • Best time of year. It stands highest in the middle of the night around December — 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. ≈ 872 thousand years at Voyager 1's speed (17 km/s).

Properties

density gcc
3.82
diameter km
7220.0092
discovery facility
Transiting Exoplanet Survey Satellite (TESS)
discovery method
Transit
discovery year
2024
dist ly
49.622
eq temp k
758
host star teff
3485
inclination
89.99
insolation
229.4579
mag
11.62
mass earth
0.126
name
GJ 238 b
orbital period days
1.7447
radius earth
0.566
semi major au
0.0212
spect
M2.5 V
sys num planets
1
sys num stars
1
tidally locked
yes
tidally locked inferred
yes

About GJ 238 b

GJ 238 b is an uncommon exoplanet. It lies about 49.6 light-years from Earth, shines at apparent magnitude 11.62, has spectral type M2.5 V and has an equilibrium temperature near 758 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 11.62, a small backyard telescope will bring it into view.

Like any astronomical target, GJ 238 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 238 b is an uncommon exoplanet

GJ 238 b scores 27 points on Spacedle's rarity scale, which places it in the uncommon tier. Another 7 points would lift it into a rarer tier.

That score comes from 4 science badges — Confirmed exoplanet, Tidally locked, Found by TESS and Orbits a red dwarf — 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.