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Epic exoplanet 55 EP

TOI-1173 b

RA 197.6831° · Dec 70.7680° · exoplanet

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Score breakdown

· 7 badges
55 pts · Epic
Epic 78 pts → Anomaly
  • Puffy low-density world +12
  • Two suns in its sky +12
  • Tidally locked +10
  • Orbits a Sun-like star +8
  • Confirmed exoplanet +5
  • Gas giant +4
  • Found by TESS +4
Total score 55

23 more points to reach Anomaly.

Badges

  • Confirmed exoplanet · +5
  • Gas giant · +4
  • Tidally locked · +10
  • Puffy low-density world · +12
  • Found by TESS · +4
  • Orbits a Sun-like star · +8
  • Two suns in its sky · +12

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.

Sense of scale

  • In perspective. Far away by human standards, yet still a local address inside the Milky Way's spiral arms.

Find it in the sky

  • How to spot it. At magnitude 11 you'll want a small backyard telescope.
  • Never sets. So far north that from Britain, Canada or northern Europe it never dips below the horizon — it is up every clear night of the year.
  • Best time of year. It stands highest in the middle of the night around April — that's when to go looking.

Could we get there?

  • Verdict. Hopelessly far for any craft humanity can build today.

Properties

density gcc
0.195
diameter km
117229.478
discovery facility
Transiting Exoplanet Survey Satellite (TESS)
discovery method
Transit
discovery year
2024
dist ly
431.6773
eccentricity
0.023
eq temp k
868
host star teff
5350
inclination
87.228
insolation
132
mag
11.038
mass earth
27.4
multi star system
yes
name
TOI-1173 b
orbital period days
7.0647
radius earth
9.19
semi major au
0.0696
spect
G9
sys num planets
1
sys num stars
2
tidally locked
yes
tidally locked inferred
yes

About TOI-1173 b

TOI-1173 b is an epic exoplanet. It lies about 431.7 light-years from Earth, shines at apparent magnitude 11.04, has spectral type G9 and has an equilibrium temperature near 868 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 11.04, a small backyard telescope will bring it into view.

Like any astronomical target, TOI-1173 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 TOI-1173 b is an epic exoplanet

TOI-1173 b scores 55 points on Spacedle's rarity scale, which places it in the epic tier. Another 23 points would lift it into a rarer tier.

That score comes from 7 science badges — Confirmed exoplanet, Gas giant, Tidally locked, Puffy low-density world, Found by TESS, Orbits a Sun-like star and Two suns in its sky — 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.