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Epic exoplanet 51 EP

WASP-31 b

RA 169.4389° · Dec -19.0548° · exoplanet

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Score breakdown

· 6 badges
51 pts · Epic
Epic 78 pts → Anomaly
  • Lava world +14
  • Puffy low-density world +12
  • Tidally locked +10
  • Distant (over 1,000 light-years) +6
  • Confirmed exoplanet +5
  • Gas giant +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
  • Puffy low-density world · +12

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 11.7 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 March — that's when to go looking.

Properties

density gcc
0.172
diameter km
221485.9006
discovery facility
SuperWASP
discovery method
Transit
discovery year
2010
dist ly
1251.8813
eccentricity
0
eq temp k
1423.7
host star teff
6302
inclination
84.41
insolation
970.9417
mag
11.658
mass earth
151.916
name
WASP-31 b
orbital period days
3.4059
radius earth
17.363
semi major au
0.0466
sys num planets
1
sys num stars
1
tidally locked
yes
tidally locked inferred
yes

About WASP-31 b

WASP-31 b is an epic exoplanet. It lies about 1,251.9 light-years from Earth, shines at apparent magnitude 11.66, has an equilibrium temperature near 1,424 K and spans roughly 17.36 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 11.66, a small backyard telescope will bring it into view.

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

WASP-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 6 science badges — Confirmed exoplanet, Distant (over 1,000 light-years), Gas giant, Lava world, Tidally locked and Puffy low-density 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.