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Epic exoplanet 51 EP

NGTS-31 b

RA 80.4213° · Dec -38.6568° · exoplanet

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Score breakdown

· 7 badges
51 pts · Epic
Epic 78 pts → Anomaly
  • Lava world +14
  • Tidally locked +10
  • Orbits a Sun-like star +8
  • Distant (over 1,000 light-years) +6
  • Confirmed exoplanet +5
  • Gas giant +4
  • Found by TESS +4
Total score 51

27 more points to reach Anomaly.

Badges

  • Confirmed exoplanet · +5
  • Distant (over 1,000 light-years) · +6
  • Gas giant · +4
  • Lava world · +14
  • Tidally locked · +10
  • Found by TESS · +4
  • Orbits a Sun-like star · +8

Trivia

What makes it special

  • Lava world. Its surface is almost certainly an ocean of molten rock, kept liquid by the star it hugs.

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

  • 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. 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. Far away by human standards, yet still a local address inside the Milky Way's spiral arms.

Find it in the sky

  • How to spot it. At magnitude 13.5 it is far too faint for the eye: this one belongs to cameras and long exposures.
  • 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.

Properties

density gcc
0.3
diameter km
230204.2394
discovery facility
Transiting Exoplanet Survey Satellite (TESS)
discovery method
Transit
discovery year
2025
dist ly
1622.2217
eccentricity
0
eq temp k
1410
host star teff
5710
inclination
85.6
insolation
643
mag
13.519
mass earth
355.9678
name
NGTS-31 b
orbital period days
4.1627
radius earth
18.0465
semi major au
0.064
sys num planets
1
sys num stars
1
tidally locked
yes
tidally locked inferred
yes

About NGTS-31 b

NGTS-31 b is an epic exoplanet. It lies about 1,622.2 light-years from Earth, shines at apparent magnitude 13.52, has an equilibrium temperature near 1,410 K and spans roughly 18.05 Earth radii.

Its surface is almost certainly an ocean of molten rock, kept liquid by the star it hugs.

How to see it

At apparent magnitude 13.52, it takes a larger telescope or a long-exposure image to capture.

Like any astronomical target, NGTS-31 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 NGTS-31 b is an epic exoplanet

NGTS-31 b scores 51 points on Spacedle's rarity scale, which places it in the epic tier. Another 27 points would lift it into a rarer tier.

That score comes from 7 science badges — Confirmed exoplanet, Distant (over 1,000 light-years), Gas giant, Lava world, Tidally locked, Found by TESS and Orbits a Sun-like star — 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.