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Rare exoplanet 48 EP

K2-9 b

RA 176.2637° · Dec 0.0054° · exoplanet

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Score breakdown

· 4 badges
48 pts · Rare
Rare 50 pts → Epic
  • In the habitable zone +30
  • Orbits a red dwarf +8
  • Confirmed exoplanet +5
  • Sub-Neptune +5
Total score 48

2 more points to reach Epic.

Badges

  • Confirmed exoplanet · +5
  • In the habitable zone · +30
  • Sub-Neptune · +5
  • Orbits a red dwarf · +8

Trivia

What makes it special

  • Goldilocks zone. Sits where it's neither too hot nor too cold — liquid water could exist on a surface here.

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. Too light to be solid rock and too heavy to be all gas: most likely a deep global ocean or a thick steamy envelope over a rocky core.
  • What the zone means. The habitable zone is only about temperature: it is the band where liquid water could survive on a surface. It is a promising address, not evidence of anything living.

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 15.9 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.

Properties

density gcc
2.74
diameter km
28701.45
discovery facility
K2
discovery method
Transit
discovery year
2015
dist ly
270.5891
eq temp k
314
habitable zone
yes
host star teff
3390
inclination
87.983
insolation
1.36
mag
15.86
mass earth
5.69
name
K2-9 b
orbital period days
18.4498
radius earth
2.25
semi major au
0.091
spect
M2.5 V
sys num planets
1
sys num stars
1

About K2-9 b

K2-9 b is a rare exoplanet. It lies about 270.6 light-years from Earth, shines at apparent magnitude 15.86, has spectral type M2.5 V and has an equilibrium temperature near 314 K.

Sits where it's neither too hot nor too cold — liquid water could exist on a surface here.

How to see it

At apparent magnitude 15.86, it takes a larger telescope or a long-exposure image to capture.

Like any astronomical target, K2-9 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 K2-9 b is a rare exoplanet

K2-9 b scores 48 points on Spacedle's rarity scale, which places it in the rare tier. Another 2 points would lift it into a rarer tier.

That score comes from 4 science badges — Confirmed exoplanet, In the habitable zone, Sub-Neptune 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.