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Trash exoplanet 10 EP

K2-17 b

RA 178.3297° · Dec 6.4123° · exoplanet

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Score breakdown

· 2 badges
10 pts · Trash
Trash 15 pts → Common
  • Confirmed exoplanet +5
  • Sub-Neptune +5
Total score 10

5 more points to reach Common.

Badges

  • Confirmed exoplanet · +5
  • Sub-Neptune · +5

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. 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.

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 13.4 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.

Getting there

  • Aboard Voyager 1. ≈ 7.2 million years at Voyager 1's speed (17 km/s).

Properties

density gcc
2.77
diameter km
28446.326
discovery facility
K2
discovery method
Transit
discovery year
2015
dist ly
408.0407
eccentricity
0.18
eq temp k
487
host star teff
4320
inclination
89.08
insolation
4.91
mag
13.411
mass earth
5.6
name
K2-17 b
orbital period days
17.9675
radius earth
2.23
semi major au
0.119
spect
K7
sys num planets
1
sys num stars
1

About K2-17 b

K2-17 b is a trash exoplanet. It lies about 408 light-years from Earth, shines at apparent magnitude 13.41, has spectral type K7 and has an equilibrium temperature near 487 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 13.41, it takes a larger telescope or a long-exposure image to capture.

Like any astronomical target, K2-17 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 K2-17 b is a trash exoplanet

K2-17 b scores 10 points on Spacedle's rarity scale, which places it in the trash tier. Another 5 points would lift it into a rarer tier.

That score comes from 2 science badges — Confirmed exoplanet and Sub-Neptune — 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.