About 55 Cnc b
55 Cnc b is an uncommon exoplanet. It lies about 41 light-years from Earth, has an equilibrium temperature near 700 K, spans roughly 13.9 Earth radii and weighs about 263.98 Earth masses.
Crammed into a system of five or more planets.
Uncommon exoplanet 29 EP
55 Cnc b
RA 133.1468° · Dec 28.3298° · exoplanet
Score breakdown
· 4 badgesUncommon 33 pts → Rare
- Richly packed system +14
- Multi-planet system +6
- Confirmed exoplanet +5
- Gas giant +4
Total score 29
4 more points to reach Rare.
Badges
- Confirmed exoplanet · +5
- Gas giant · +4
- Multi-planet system · +6
- Richly packed system · +14
Trivia
What makes it special
- Packed system. Crammed into a system of five or more planets.
Could we get there?
- Verdict. Hopelessly far for any craft humanity can build today.
Getting there
- Aboard Voyager 1. ≈ 721.3 thousand years at Voyager 1's speed (17 km/s).
- Fastest probe ever. ≈ 64.1 thousand years even at the Parker Solar Probe's 192 km/s.
- At 10% light speed. ≈ 410 years in a starship at a tenth of light speed.
- Distance. 41 light-years from Earth.
Look-back time
- Look-back time. The light you'd see left around the year 1985.
Saying hello
- Say hello. A radio message and its reply would take 82.1 years round-trip.
Standing on it
- A year here. A full year lasts just 14.7 Earth days.
By the numbers
- Size. About 13.9× the width of Earth.
- Volume. About 2686 Earths could fit inside it.
- Mass. Roughly 264× Earth's mass — about 0.8 Jupiters.
- Your weight. You'd weigh about 1.4× your Earth weight standing here.
- Density. Less dense than water — drop it in a big enough ocean and it would float.
- Temperature. A scorching 427°C on average.
How we found it
- Discovery. Found by Lick Observatory using the radial velocity method.
Cosmic context
- Crowded system. One of at least 7 planets orbiting its star.
Properties
- density gcc
- 0.54
- discovery facility
- Lick Observatory
- discovery method
- Radial Velocity
- dist ly
- 41.0484
- eccentricity
- 0.0029
- eq temp k
- 700
- insolation
- 45.6336
- mass earth
- 263.9785
- name
- 55 Cnc b
- orbital period days
- 14.6516
- radius earth
- 13.9
- sys num planets
- 7
How to see it
Like any astronomical target, 55 Cnc 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 is an uncommon exoplanet
55 Cnc b scores 29 points on Spacedle's rarity scale, which places it in the uncommon tier. Another 4 points would lift it into a rarer tier.
That score comes from 4 science badges — Confirmed exoplanet, Gas giant, Multi-planet system and Richly packed system — 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.