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Rare exoplanet 46 EP

GJ 876 d

RA 343.3240° · Dec -14.2666° · exoplanet

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Score breakdown

· 6 badges
46 pts · Rare
Rare 50 pts → Epic
  • Nearby (<25 ly) +12
  • Tidally locked +10
  • Orbits a red dwarf +8
  • Multi-planet system +6
  • Confirmed exoplanet +5
  • Sub-Neptune +5
Total score 46

4 more points to reach Epic.

Badges

  • Confirmed exoplanet · +5
  • Nearby (<25 ly) · +12
  • Sub-Neptune · +5
  • Tidally locked · +10
  • Multi-planet system · +6
  • 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. 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.
  • Crowded system. One of at least 4 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 10.2 you'll want a small backyard telescope.
  • Southern sky. It rides the southern half of the sky — an easier target the further south you are.
  • 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
2.37
diameter km
32018.062
discovery facility
W. M. Keck Observatory
discovery method
Radial Velocity
discovery year
2005
dist ly
15.2483
eccentricity
0.207
eq temp k
603.09
host star teff
3293.74
inclination
59
insolation
28.6429
mag
10.16
mass earth
6.83
name
GJ 876 d
orbital period days
1.9378
radius earth
2.51
semi major au
0.0208
spect
M2.5V
sys num planets
4
sys num stars
1
tidally locked
yes
tidally locked inferred
yes

About GJ 876 d

GJ 876 d is a rare exoplanet. It lies about 15.2 light-years from Earth, shines at apparent magnitude 10.16, has spectral type M2.5V and has an equilibrium temperature near 603 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 10.16, a small backyard telescope will bring it into view.

Like any astronomical target, GJ 876 d 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 876 d is a rare exoplanet

GJ 876 d scores 46 points on Spacedle's rarity scale, which places it in the rare tier. Another 4 points would lift it into a rarer tier.

That score comes from 6 science badges — Confirmed exoplanet, Nearby (<25 ly), Sub-Neptune, Tidally locked, Multi-planet 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.