About 55 Cnc B b
55 Cnc B b is a rare exoplanet. It lies about 40.7 light-years from Earth, has an equilibrium temperature near 395 K, spans roughly 1.69 Earth radii and weighs about 3.5 Earth masses.
Crammed into a system of five or more planets.
Rare exoplanet 33 EP
55 Cnc B b
RA 133.1679° · Dec 28.3153° · exoplanet
Score breakdown
· 4 badgesRare 46 pts → Epic
- Richly packed system +14
- Super-Earth +8
- Multi-planet system +6
- Confirmed exoplanet +5
Total score 33
13 more points to reach Epic.
Badges
- Confirmed exoplanet · +5
- Super-Earth · +8
- 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. ≈ 715.1 thousand years at Voyager 1's speed (17 km/s).
- Fastest probe ever. ≈ 63.5 thousand years even at the Parker Solar Probe's 192 km/s.
- At 10% light speed. ≈ 407 years in a starship at a tenth of light speed.
- Distance. 40.7 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 81.4 years round-trip.
Standing on it
- A year here. A full year lasts just 6.8 Earth days.
By the numbers
- Size. About 1.7× the width of Earth.
- Volume. About 4.8 Earths could fit inside it.
- Mass. About 3.5× the mass of Earth.
- Your weight. You'd weigh about 1.2× your Earth weight standing here.
- Temperature. A scorching 122°C on average.
How we found it
- Discovery. Found by Mauna Kea Observatory using the radial velocity method.
Cosmic context
- Crowded system. One of at least 7 planets orbiting its star.
Properties
- density gcc
- 3.98
- discovery facility
- Mauna Kea Observatory
- discovery method
- Radial Velocity
- dist ly
- 40.6955
- eccentricity
- 0
- eq temp k
- 395.41
- insolation
- 4.0271
- mass earth
- 3.5
- name
- 55 Cnc B b
- orbital period days
- 6.7994
- radius earth
- 1.69
- sys num planets
- 7
How to see it
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 a rare exoplanet
55 Cnc B b scores 33 points on Spacedle's rarity scale, which places it in the rare tier. Another 13 points would lift it into a rarer tier.
That score comes from 4 science badges — Confirmed exoplanet, Super-Earth, 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.