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Rare exoplanet 39 EP

GJ 251 b

RA 103.7002° · Dec 33.2665° · exoplanet

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Score breakdown

· 5 badges
39 pts · Rare
Rare 50 pts → Epic
  • Nearby (<25 ly) +12
  • Super-Earth +8
  • Orbits a red dwarf +8
  • Multi-planet system +6
  • Confirmed exoplanet +5
Total score 39

11 more points to reach Epic.

Badges

  • Confirmed exoplanet · +5
  • Nearby (<25 ly) · +12
  • Super-Earth · +8
  • Multi-planet system · +6
  • Orbits a red dwarf · +8

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 2 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 9.9 you'll want a small backyard telescope.
  • 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 January — that's when to go looking.

Could we get there?

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

Properties

density gcc
3.69
diameter km
22833.598
discovery facility
W. M. Keck Observatory
discovery method
Radial Velocity
discovery year
2020
dist ly
18.2014
eccentricity
0
eq temp k
336
host star teff
3342
insolation
2.37
mag
9.89
mass earth
3.85
name
GJ 251 b
orbital period days
14.237
radius earth
1.79
semi major au
0.0808
spect
M3.0 V
sys num planets
2
sys num stars
1

About GJ 251 b

GJ 251 b is a rare exoplanet. It lies about 18.2 light-years from Earth, shines at apparent magnitude 9.89, has spectral type M3.0 V and has an equilibrium temperature near 336 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 9.89, a small backyard telescope will bring it into view.

Like any astronomical target, GJ 251 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 GJ 251 b is a rare exoplanet

GJ 251 b scores 39 points on Spacedle's rarity scale, which places it in the rare tier. Another 11 points would lift it into a rarer tier.

That score comes from 5 science badges — Confirmed exoplanet, Nearby (<25 ly), Super-Earth, Multi-planet system and Orbits a red dwarf — 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.