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Rare exoplanet 45 EP

WASP-4 b

RA 353.5629° · Dec -42.0618° · exoplanet

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Score breakdown

· 6 badges
45 pts · Rare
Rare 50 pts → Epic
  • Lava world +14
  • Tidally locked +10
  • Orbits a Sun-like star +8
  • Confirmed exoplanet +5
  • Gas giant +4
  • Blasted by starlight +4
Total score 45

5 more points to reach Epic.

Badges

  • Confirmed exoplanet · +5
  • Gas giant · +4
  • Lava world · +14
  • Tidally locked · +10
  • 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 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 September — that's when to go looking.

Properties

density gcc
0.6472
diameter km
192885.4154
discovery facility
SuperWASP
discovery method
Transit
discovery year
2007
dist ly
871.5084
eccentricity
0.0053
eq temp k
1653
host star teff
5436
inclination
88.05
insolation
1188.6219
mag
12.483
mass earth
381.3941
name
WASP-4 b
orbital period days
1.3382
radius earth
15.1209
semi major au
0.0226
spect
G8
sys num planets
1
sys num stars
1
tidally locked
yes
tidally locked inferred
yes

About WASP-4 b

WASP-4 b is a rare exoplanet. It lies about 871.5 light-years from Earth, shines at apparent magnitude 12.48, has spectral type G8 and has an equilibrium temperature near 1,653 K.

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

How to see it

At apparent magnitude 12.48, it takes a larger telescope or a long-exposure image to capture.

Like any astronomical target, WASP-4 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-4 b is a rare exoplanet

WASP-4 b scores 45 points on Spacedle's rarity scale, which places it in the rare tier. Another 5 points would lift it into a rarer tier.

That score comes from 6 science badges — Confirmed exoplanet, Gas giant, Lava world, Tidally locked, 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.