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Epic exoplanet 57 EP

55 Cnc B b

RA 133.1679° · Dec 28.3153° · exoplanet

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Score breakdown

· 6 badges
57 pts · Epic
Epic 78 pts → Anomaly
  • Richly packed system +14
  • Two suns in its sky +12
  • Tidally locked +10
  • Super-Earth +8
  • Orbits a red dwarf +8
  • Confirmed exoplanet +5
Total score 57

21 more points to reach Anomaly.

Badges

  • Confirmed exoplanet · +5
  • Super-Earth · +8
  • Tidally locked · +10
  • Richly packed system · +14
  • Orbits a red dwarf · +8
  • Two suns in its sky · +12

Trivia

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. Its density says rock, though lighter than Earth's mix: probably less iron, or a thick shell of water and ice over the top.
  • Crowded system. One of at least 7 planets orbiting its star.

Sense of scale

  • In perspective. Inside our stellar backyard: every radio broadcast humanity has ever made has already swept past it.

Find it in the sky

  • How to spot it. At magnitude 13.2 it is far too faint for the eye: this one belongs to cameras and long exposures.
  • Northern sky. It rides the northern half of the sky — an easier target the further north you are.
  • Best time of year. It stands highest in the middle of the night around February — that's when to go looking.

Could we get there?

  • Verdict. Hopelessly far for any craft humanity can build today.

Properties

density gcc
3.98
diameter km
21557.978
discovery facility
Mauna Kea Observatory
discovery method
Radial Velocity
discovery year
2025
dist ly
40.6955
eccentricity
0
eq temp k
395.41
host star teff
3286
insolation
4.0271
mag
13.152
mass earth
3.5
multi star system
yes
name
55 Cnc B b
orbital period days
6.7994
radius earth
1.69
semi major au
0.044
spect
M4.5 V
sys num planets
7
sys num stars
2
tidally locked
yes
tidally locked inferred
yes

About 55 Cnc B b

55 Cnc B b is an epic exoplanet. It lies about 40.7 light-years from Earth, shines at apparent magnitude 13.15, has spectral type M4.5 V and has an equilibrium temperature near 395 K.

It orbits closer to its star than Mercury does to the Sun, completing a lap in less time than Mercury takes.

How to see it

At apparent magnitude 13.15, it takes a larger telescope or a long-exposure image to capture.

Like any astronomical target, 55 Cnc B 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 55 Cnc B b is an epic exoplanet

55 Cnc B b scores 57 points on Spacedle's rarity scale, which places it in the epic tier. Another 21 points would lift it into a rarer tier.

That score comes from 6 science badges — Confirmed exoplanet, Super-Earth, Tidally locked, Richly packed system, Orbits a red dwarf and Two suns in its sky — 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.