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Rare exoplanet 47 EP

HATS-51 b

RA 102.8474° · Dec -29.0587° · exoplanet

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Score breakdown

· 6 badges
47 pts · Rare
Rare 50 pts → Epic
  • 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
Total score 47

3 more points to reach Epic.

Badges

  • Confirmed exoplanet · +5
  • Distant (over 1,000 light-years) · +6
  • Gas giant · +4
  • Lava world · +14
  • Tidally locked · +10
  • 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 12.5 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 January — that's when to go looking.

Properties

density gcc
0.34
diameter km
201607.7866
discovery facility
HATSouth
discovery method
Transit
discovery year
2017
dist ly
1270.6059
eccentricity
0.33
eq temp k
1553
host star teff
5758
inclination
87.1
insolation
740.2246
mag
12.525
mass earth
244.0934
name
HATS-51 b
orbital period days
3.3489
radius earth
15.8047
semi major au
0.0464
sys num planets
1
sys num stars
1
tidally locked
yes
tidally locked inferred
yes

About HATS-51 b

HATS-51 b is a rare exoplanet. It lies about 1,270.6 light-years from Earth, shines at apparent magnitude 12.53, has an equilibrium temperature near 1,553 K and spans roughly 15.8 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 12.53, it takes a larger telescope or a long-exposure image to capture.

Like any astronomical target, HATS-51 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-51 b is a rare exoplanet

HATS-51 b scores 47 points on Spacedle's rarity scale, which places it in the rare tier. Another 3 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 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.