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Rare exoplanet 49 EP

K2-291 b

RA 76.4459° · Dec 21.5482° · exoplanet

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Score breakdown

· 5 badges
49 pts · Rare
Rare 50 pts → Epic
  • Denser than iron +18
  • Tidally locked +10
  • Super-Earth +8
  • Orbits a Sun-like star +8
  • Confirmed exoplanet +5
Total score 49

1 more point to reach Epic.

Badges

  • Confirmed exoplanet · +5
  • Super-Earth · +8
  • Tidally locked · +10
  • Denser than iron · +18
  • Orbits a Sun-like star · +8

Trivia

Hard to believe

  • Denser than iron. It is packed tighter than solid iron — whatever it is made of, it is not ordinary rock.

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. Denser than Earth — a solid world of rock and iron, with no meaningful atmosphere to speak of by mass.

Sense of scale

  • In perspective. Far away by human standards, yet still a local address inside the Milky Way's spiral arms.

Find it in the sky

  • How to spot it. At magnitude 10 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 December — that's when to go looking.

Could we get there?

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

Properties

density gcc
8.84
diameter km
20269.6018
discovery facility
K2
discovery method
Transit
discovery year
2019
dist ly
293.7237
eccentricity
0
eq temp k
1278
host star teff
5520
inclination
85.26
insolation
633
mag
10.014
mass earth
6.49
name
K2-291 b
orbital period days
2.2252
radius earth
1.589
semi major au
0.0326
sys num planets
1
sys num stars
1
tidally locked
yes
tidally locked inferred
yes

About K2-291 b

K2-291 b is a rare exoplanet. It lies about 293.7 light-years from Earth, shines at apparent magnitude 10.01, has an equilibrium temperature near 1,278 K and spans roughly 1.59 Earth radii.

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 10.01, a small backyard telescope will bring it into view.

Like any astronomical target, K2-291 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 K2-291 b is a rare exoplanet

K2-291 b scores 49 points on Spacedle's rarity scale, which places it in the rare tier. Another 1 point would lift it into a rarer tier.

That score comes from 5 science badges — Confirmed exoplanet, Super-Earth, Tidally locked, Denser than iron and Orbits a Sun-like star — 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.