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Rare exoplanet 49 EP

GJ 3929 b

RA 239.5776° · Dec 35.4081° · exoplanet

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Score breakdown

· 6 badges
49 pts · Rare
Rare 50 pts → Epic
  • Earth-sized +16
  • Tidally locked +10
  • Orbits a red dwarf +8
  • Multi-planet system +6
  • Confirmed exoplanet +5
  • Found by TESS +4
Total score 49

1 more point to reach Epic.

Badges

  • Confirmed exoplanet · +5
  • Earth-sized · +16
  • Tidally locked · +10
  • Multi-planet system · +6
  • Found by TESS · +4
  • 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 2 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 12.7 it is far too faint for the eye: this one belongs to cameras and long exposures.
  • 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.

Properties

density gcc
7.3
diameter km
13904.258
discovery facility
Transiting Exoplanet Survey Satellite (TESS)
discovery method
Transit
discovery year
2022
dist ly
51.5636
eccentricity
0
eq temp k
568
host star teff
3384
inclination
88.442
insolation
17.3
mag
12.675
mass earth
1.75
name
GJ 3929 b
orbital period days
2.6162
radius earth
1.09
semi major au
0.0252
spect
M3.5 V
sys num planets
2
sys num stars
1
tidally locked
yes
tidally locked inferred
yes

About GJ 3929 b

GJ 3929 b is a rare exoplanet. It lies about 51.6 light-years from Earth, shines at apparent magnitude 12.68, has spectral type M3.5 V and has an equilibrium temperature near 568 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 12.68, it takes a larger telescope or a long-exposure image to capture.

Like any astronomical target, GJ 3929 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 3929 b is a rare exoplanet

GJ 3929 b scores 49 points on Spacedle's rarity scale, which places it in the rare tier. Another 1 point would lift it into a rarer tier.

That score comes from 6 science badges — Confirmed exoplanet, Earth-sized, Tidally locked, Multi-planet system, Found by TESS 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.