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Epic exoplanet 69 EP

GJ 273 b

RA 111.8521° · Dec 5.2258° · exoplanet

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Score breakdown

· 6 badges
69 pts · Epic
Epic 78 pts → Anomaly
  • In the habitable zone +30
  • Nearby (<25 ly) +12
  • Super-Earth +8
  • Orbits a red dwarf +8
  • Multi-planet system +6
  • Confirmed exoplanet +5
Total score 69

9 more points to reach Anomaly.

Badges

  • Confirmed exoplanet · +5
  • Nearby (<25 ly) · +12
  • In the habitable zone · +30
  • Super-Earth · +8
  • Multi-planet system · +6
  • Orbits a red dwarf · +8

Trivia

What makes it special

  • Goldilocks zone. Sits where it's neither too hot nor too cold — liquid water could exist on a surface here.

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.
  • What the zone means. The habitable zone is only about temperature: it is the band where liquid water could survive on a surface. It is a promising address, not evidence of anything living.
  • 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 9.8 you'll want a small backyard telescope.
  • Seen from everywhere. It sits almost on the celestial equator, so it can be seen from essentially anywhere on Earth.

Properties

density gcc
4.61
diameter km
19261.862
discovery facility
La Silla Observatory
discovery method
Radial Velocity
discovery year
2017
dist ly
19.3134
eccentricity
0.1
eq temp k
292.47
habitable zone
yes
host star teff
3382
insolation
1.06
mag
9.84
mass earth
2.89
name
GJ 273 b
orbital period days
18.6498
radius earth
1.51
semi major au
0.0911
spect
M3.5
sys num planets
2
sys num stars
1

About GJ 273 b

GJ 273 b is an epic exoplanet. It lies about 19.3 light-years from Earth, shines at apparent magnitude 9.84, has spectral type M3.5 and has an equilibrium temperature near 292 K.

Sits where it's neither too hot nor too cold — liquid water could exist on a surface here.

How to see it

At apparent magnitude 9.84, a small backyard telescope will bring it into view.

Like any astronomical target, GJ 273 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 273 b is an epic exoplanet

GJ 273 b scores 69 points on Spacedle's rarity scale, which places it in the epic tier. Another 9 points would lift it into a rarer tier.

That score comes from 6 science badges — Confirmed exoplanet, Nearby (<25 ly), In the habitable zone, Super-Earth, 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.