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Uncommon exoplanet 29 EP

AU Mic b

RA 311.2911° · Dec -31.3424° · exoplanet

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Score breakdown

· 5 badges
29 pts · Uncommon
Uncommon 34 pts → Rare
  • Tidally locked +10
  • Multi-planet system +6
  • Confirmed exoplanet +5
  • Neptune-like +4
  • Found by TESS +4
Total score 29

5 more points to reach Rare.

Badges

  • Confirmed exoplanet · +5
  • Neptune-like · +4
  • Tidally locked · +10
  • Multi-planet system · +6
  • Found by TESS · +4

Trivia

Hard to believe

  • It would float. It is less dense than water. Drop it in a big enough ocean and the whole world would bob on the surface.

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. Lighter than Neptune — a puffed-up ball of hydrogen and helium with no surface anywhere on it to stand on.
  • 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 8.8 it is just past naked-eye reach — ordinary binoculars will pull it in.
  • 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 August — that's when to go looking.

Properties

density gcc
0.49
diameter km
61102.198
discovery facility
Transiting Exoplanet Survey Satellite (TESS)
discovery method
Transit
discovery year
2020
dist ly
31.7092
eccentricity
0.07
eq temp k
554.8
host star teff
3540
inclination
88.39
insolation
21.2
mag
8.81
mass earth
8.99
name
AU Mic b
orbital period days
8.4634
radius earth
4.79
semi major au
0.07
spect
M1 V
sys num planets
4
sys num stars
1
tidally locked
yes
tidally locked inferred
yes

About AU Mic b

AU Mic b is an uncommon exoplanet. It lies about 31.7 light-years from Earth, shines at apparent magnitude 8.81, has spectral type M1 V and has an equilibrium temperature near 555 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 8.81, it is an easy target for binoculars.

Like any astronomical target, AU Mic 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 AU Mic b is an uncommon exoplanet

AU Mic b scores 29 points on Spacedle's rarity scale, which places it in the uncommon tier. Another 5 points would lift it into a rarer tier.

That score comes from 5 science badges — Confirmed exoplanet, Neptune-like, Tidally locked, Multi-planet system and Found by TESS — 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.