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Uncommon exoplanet 27 EP

TRAPPIST-1 h

RA 346.6264° · Dec -5.0435° · exoplanet

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Score breakdown

· 3 badges
27 pts · Uncommon
Uncommon 34 pts → Rare
  • Richly packed system +14
  • Orbits a red dwarf +8
  • Confirmed exoplanet +5
Total score 27

7 more points to reach Rare.

Badges

  • Confirmed exoplanet · +5
  • Richly packed system · +14
  • Orbits a red dwarf · +8

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 7 planets orbiting its star.

Sense of scale

  • In perspective. Inside our stellar backyard: every radio broadcast humanity has ever made has already swept past it.

Find it in the sky

  • How to spot it. At magnitude 17 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 September — that's when to go looking.

Could we get there?

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

Properties

density gcc
4.1628
diameter km
9630.931
discovery facility
Multiple Observatories
discovery method
Transit
discovery year
2017
dist ly
40.5408
eccentricity
0.0057
eq temp k
171.7
host star teff
2566
inclination
89.805
insolation
0.144
mag
17.02
mass earth
0.326
name
TRAPPIST-1 h
orbital period days
18.7729
radius earth
0.755
semi major au
0.0619
spect
M8.0 V
sys num planets
7
sys num stars
1

About TRAPPIST-1 h

TRAPPIST-1 h is an uncommon exoplanet. It lies about 40.5 light-years from Earth, shines at apparent magnitude 17.02, has spectral type M8.0 V and has an equilibrium temperature near 172 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 17.02, it takes a larger telescope or a long-exposure image to capture.

Like any astronomical target, TRAPPIST-1 h 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 TRAPPIST-1 h is an uncommon exoplanet

TRAPPIST-1 h scores 27 points on Spacedle's rarity scale, which places it in the uncommon tier. Another 7 points would lift it into a rarer tier.

That score comes from 3 science badges — Confirmed exoplanet, Richly packed 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.