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Common exoplanet 20 EP

GJ 3942 b

RA 242.2645° · Dec 52.9441° · exoplanet

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Score breakdown

· 3 badges
20 pts · Common
Common 22 pts → Uncommon
  • Tidally locked +10
  • Confirmed exoplanet +5
  • Sub-Neptune +5
Total score 20

2 more points to reach Uncommon.

Badges

  • Confirmed exoplanet · +5
  • Sub-Neptune · +5
  • Tidally locked · +10

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. 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 10.2 you'll want a small backyard telescope.
  • Northern sky. It rides the northern half of the sky — an easier target the further north you are.
  • Best time of year. It stands highest in the middle of the night around May — 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. ≈ 970.3 thousand years at Voyager 1's speed (17 km/s).

Properties

density gcc
2.31
diameter km
32783.434
discovery facility
Roque de los Muchachos Observatory
discovery method
Radial Velocity
discovery year
2017
dist ly
55.214
eccentricity
0.121
eq temp k
590
host star teff
3867
insolation
20.5207
mag
10.166
mass earth
7.14
name
GJ 3942 b
orbital period days
6.905
radius earth
2.57
semi major au
0.0608
spect
M0
sys num planets
1
sys num stars
1
tidally locked
yes
tidally locked inferred
yes

About GJ 3942 b

GJ 3942 b is a common exoplanet. It lies about 55.2 light-years from Earth, shines at apparent magnitude 10.17, has spectral type M0 and has an equilibrium temperature near 590 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 10.17, a small backyard telescope will bring it into view.

Like any astronomical target, GJ 3942 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 GJ 3942 b is a common exoplanet

GJ 3942 b scores 20 points on Spacedle's rarity scale, which places it in the common tier. Another 2 points would lift it into a rarer tier.

That score comes from 3 science badges — Confirmed exoplanet, Sub-Neptune and Tidally locked — 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.