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Rare exoplanet 47 EP

55 Cnc c

RA 133.1468° · Dec 28.3298° · exoplanet

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Score breakdown

· 5 badges
47 pts · Rare
Rare 50 pts → Epic
  • Richly packed system +14
  • Its star is visible to the naked eye +12
  • Two suns in its sky +12
  • Confirmed exoplanet +5
  • Gas giant +4
Total score 47

3 more points to reach Epic.

Badges

  • Confirmed exoplanet · +5
  • Gas giant · +4
  • Richly packed system · +14
  • Its star is visible to the naked eye · +12
  • Two suns in its sky · +12

Trivia

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.
  • 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 6 you can see it with your own eyes from a dark site.
  • 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.

Properties

density gcc
0.486
diameter km
108555.262
discovery facility
McDonald Observatory
discovery method
Radial Velocity
discovery year
2004
dist ly
41.0484
eccentricity
0.088
eq temp k
499.27
host star teff
5198
inclination
89.73
insolation
10.4149
mag
5.9508
mass earth
54.4738
multi star system
yes
name
55 Cnc c
orbital period days
44.3936
radius earth
8.51
semi major au
0.247
spect
G8 V
sys num planets
7
sys num stars
2

About 55 Cnc c

55 Cnc c is a rare exoplanet. It lies about 41 light-years from Earth, shines at apparent magnitude 5.95, has spectral type G8 V and has an equilibrium temperature near 499 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 5.95, it can be glimpsed with the unaided eye under dark skies.

Like any astronomical target, 55 Cnc c 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 c is a rare exoplanet

55 Cnc c 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 5 science badges — Confirmed exoplanet, Gas giant, Richly packed system, Its star is visible to the naked eye 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.