About 51 Eri b
51 Eri b is an epic exoplanet. It lies about 97.1 light-years from Earth, shines at apparent magnitude 5.21, has spectral type F0 IV and has an equilibrium temperature near 807 K.
Around 534°C — hotter than a self-cleaning oven.
Epic exoplanet 64 EP
51 Eri b
RA 69.4007° · Dec -2.4738° · exoplanet
Score breakdown
· 6 badgesEpic 78 pts → Anomaly
- Directly imaged +16
- Its star is visible to the naked eye +12
- Two suns in its sky +12
- Long-period world +10
- Eccentric orbit +9
- Confirmed exoplanet +5
Total score 64
14 more points to reach Anomaly.
Badges
- Confirmed exoplanet · +5
- Long-period world · +10
- Eccentric orbit · +9
- Directly imaged · +16
- Its star is visible to the naked eye · +12
- Two suns in its sky · +12
Trivia
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 5.2 you can see it with your own eyes from a dark site.
- Seen from everywhere. It sits almost on the celestial equator, so it can be seen from essentially anywhere on Earth.
- Best time of year. It stands highest in the middle of the night around November — that's when to go looking.
Could we get there?
- Verdict. Hopelessly far for any craft humanity can build today.
Getting there
- Aboard Voyager 1. ≈ 1.7 million years at Voyager 1's speed (17 km/s).
- Fastest probe ever. ≈ 151.5 thousand years even at the Parker Solar Probe's 192 km/s.
- At 10% light speed. ≈ 971 years in a starship at a tenth of light speed.
Properties
- discovery facility
- Gemini Observatory
- discovery method
- Imaging
- discovery year
- 2015
- dist ly
- 97.0559
- eccentricity
- 0.57
- eq temp k
- 807
- host star teff
- 7422
- inclination
- 141
- insolation
- 0.0529
- mag
- 5.2115
- mass earth
- 3464.3296
- multi star system
- yes
- name
- 51 Eri b
- orbital period days
- 9100
- semi major au
- 10.4
- spect
- F0 IV
- sys num planets
- 1
- sys num stars
- 3
How to see it
At apparent magnitude 5.21, it can be glimpsed with the unaided eye under dark skies.
Like any astronomical target, 51 Eri 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 51 Eri b is an epic exoplanet
51 Eri b scores 64 points on Spacedle's rarity scale, which places it in the epic tier. Another 14 points would lift it into a rarer tier.
That score comes from 6 science badges — Confirmed exoplanet, Long-period world, Eccentric orbit, Directly imaged, 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.