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Rare exoplanet 35 EP

K2-239 d

RA 160.5941° · Dec 4.4414° · exoplanet

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Score breakdown

· 4 badges
35 pts · Rare
Rare 50 pts → Epic
  • Earth-sized +16
  • Orbits a red dwarf +8
  • Multi-planet system +6
  • Confirmed exoplanet +5
Total score 35

15 more points to reach Epic.

Badges

  • Confirmed exoplanet · +5
  • Earth-sized · +16
  • Multi-planet system · +6
  • Orbits a red dwarf · +8

Trivia

What makes it special

  • Earth-sized. Genuinely comparable to Earth in size. Worlds in this narrow band are the ones every next-generation telescope is being pointed at.

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.
  • Crowded system. One of at least 3 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 14.6 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.

Properties

density gcc
5.66
diameter km
14031.82
discovery facility
K2
discovery method
Transit
discovery year
2018
dist ly
101.3853
eq temp k
399
host star teff
3420
inclination
89.43
insolation
3.4099
mag
14.632
mass earth
1.37
name
K2-239 d
orbital period days
10.115
radius earth
1.1
semi major au
0.0685
spect
M3.0 V
sys num planets
3
sys num stars
1

About K2-239 d

K2-239 d is a rare exoplanet. It lies about 101.4 light-years from Earth, shines at apparent magnitude 14.63, has spectral type M3.0 V and has an equilibrium temperature near 399 K.

Genuinely comparable to Earth in size. Worlds in this narrow band are the ones every next-generation telescope is being pointed at.

How to see it

At apparent magnitude 14.63, it takes a larger telescope or a long-exposure image to capture.

Like any astronomical target, K2-239 d 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 K2-239 d is a rare exoplanet

K2-239 d scores 35 points on Spacedle's rarity scale, which places it in the rare tier. Another 15 points would lift it into a rarer tier.

That score comes from 4 science badges — Confirmed exoplanet, Earth-sized, 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.