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Uncommon exoplanet 29 EP

K2-154 b

RA 189.0015° · Dec -2.6696° · exoplanet

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Score breakdown

· 4 badges
29 pts · Uncommon
Uncommon 34 pts → Rare
  • Tidally locked +10
  • Super-Earth +8
  • Multi-planet system +6
  • Confirmed exoplanet +5
Total score 29

5 more points to reach Rare.

Badges

  • Confirmed exoplanet · +5
  • Super-Earth · +8
  • Tidally locked · +10
  • Multi-planet system · +6

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. 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 13.9 it is far too faint for the eye: this one belongs to cameras and long exposures.
  • 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 March — that's when to go looking.

Could we get there?

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

Properties

density gcc
3.22
diameter km
25384.838
discovery facility
K2
discovery method
Transit
discovery year
2018
dist ly
421.9024
eq temp k
715
host star teff
4097
insolation
57.5
mag
13.861
mass earth
4.62
name
K2-154 b
orbital period days
3.6763
radius earth
1.99
semi major au
0.0405
spect
M0.0 V
sys num planets
2
sys num stars
1
tidally locked
yes
tidally locked inferred
yes

About K2-154 b

K2-154 b is an uncommon exoplanet. It lies about 421.9 light-years from Earth, shines at apparent magnitude 13.86, has spectral type M0.0 V and has an equilibrium temperature near 715 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 13.86, it takes a larger telescope or a long-exposure image to capture.

Like any astronomical target, K2-154 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 K2-154 b is an uncommon exoplanet

K2-154 b scores 29 points on Spacedle's rarity scale, which places it in the uncommon tier. Another 5 points would lift it into a rarer tier.

That score comes from 4 science badges — Confirmed exoplanet, Super-Earth, Tidally locked and Multi-planet 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.