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Rare exoplanet 39 EP

HATS-55 b

RA 114.2834° · Dec -32.7554° · exoplanet

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Score breakdown

· 5 badges
39 pts · Rare
Rare 50 pts → Epic
  • Lava world +14
  • Tidally locked +10
  • Distant (over 1,000 light-years) +6
  • Confirmed exoplanet +5
  • Gas giant +4
Total score 39

11 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

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 January — that's when to go looking.

Properties

density gcc
0.587
diameter km
178873.2915
discovery facility
HATSouth
discovery method
Transit
discovery year
2019
dist ly
1989.0232
eccentricity
0.092
eq temp k
1367
host star teff
6214
inclination
86.32
insolation
355.909
mag
13.525
mass earth
292.7214
name
HATS-55 b
orbital period days
4.2042
radius earth
14.0225
semi major au
0.0541
sys num planets
1
sys num stars
1
tidally locked
yes
tidally locked inferred
yes

About HATS-55 b

HATS-55 b is a rare exoplanet. It lies about 1,989 light-years from Earth, shines at apparent magnitude 13.53, has an equilibrium temperature near 1,367 K and spans roughly 14.02 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 13.53, it takes a larger telescope or a long-exposure image to capture.

Like any astronomical target, HATS-55 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-55 b is a rare exoplanet

HATS-55 b scores 39 points on Spacedle's rarity scale, which places it in the rare tier. Another 11 points would lift it into a rarer tier.

That score comes from 5 science badges — Confirmed exoplanet, Distant (over 1,000 light-years), Gas giant, Lava world and Tidally locked — 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.