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Epic exoplanet 63 EP

HATS-31 b

RA 191.7028° · Dec -24.4274° · exoplanet

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Score breakdown

· 8 badges
63 pts · Epic
Epic 78 pts → Anomaly
  • Lava world +14
  • Puffy low-density world +12
  • Tidally locked +10
  • Orbits a Sun-like star +8
  • Distant (over 1,000 light-years) +6
  • Confirmed exoplanet +5
  • Gas giant +4
  • Blasted by starlight +4
Total score 63

15 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
  • Blasted by starlight · +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 13.3 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 April — that's when to go looking.

Properties

density gcc
0.243
diameter km
234494.1631
discovery facility
HATSouth
discovery method
Transit
discovery year
2016
dist ly
2524.3626
eccentricity
0.233
eq temp k
1823
host star teff
6050
inclination
85
insolation
1619.406
mag
13.315
mass earth
279.6904
name
HATS-31 b
orbital period days
3.378
radius earth
18.3828
semi major au
0.0478
sys num planets
1
sys num stars
1
tidally locked
yes
tidally locked inferred
yes

About HATS-31 b

HATS-31 b is an epic exoplanet. It lies about 2,524.4 light-years from Earth, shines at apparent magnitude 13.31, has an equilibrium temperature near 1,823 K and spans roughly 18.38 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 13.31, it takes a larger telescope or a long-exposure image to capture.

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

HATS-31 b scores 63 points on Spacedle's rarity scale, which places it in the epic tier. Another 15 points would lift it into a rarer tier.

That score comes from 8 science badges — Confirmed exoplanet, Distant (over 1,000 light-years), Gas giant, Lava world, Tidally locked, Puffy low-density world, Blasted by starlight 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.