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Epic exoplanet 50 EP

TOI-904 c

RA 89.3713° · Dec -83.1297° · exoplanet

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Score breakdown

· 5 badges
50 pts · Epic
Epic 78 pts → Anomaly
  • In the habitable zone +30
  • Multi-planet system +6
  • Confirmed exoplanet +5
  • Sub-Neptune +5
  • Found by TESS +4
Total score 50

28 more points to reach Anomaly.

Badges

  • Confirmed exoplanet · +5
  • In the habitable zone · +30
  • Sub-Neptune · +5
  • Multi-planet system · +6
  • Found by TESS · +4

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. 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.
  • 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. 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 12.6 it is far too faint for the eye: this one belongs to cameras and long exposures.
  • Southern sky only. So far south it never rises for most of the northern hemisphere. To see it you'd have to travel to Chile, South Africa or Australia.

Properties

density gcc
2.88
diameter km
27642.6854
discovery facility
Transiting Exoplanet Survey Satellite (TESS)
discovery method
Transit
discovery year
2023
dist ly
150.3224
eq temp k
217.26
habitable zone
yes
host star teff
3770.2
inclination
89.83
insolation
0.5449
mag
12.588
mass earth
5.34
name
TOI-904 c
orbital period days
83.9997
radius earth
2.167
semi major au
0.312
sys num planets
2
sys num stars
1

About TOI-904 c

TOI-904 c is an epic exoplanet. It lies about 150.3 light-years from Earth, shines at apparent magnitude 12.59, has an equilibrium temperature near 217 K and spans roughly 2.17 Earth radii.

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 12.59, it takes a larger telescope or a long-exposure image to capture.

Like any astronomical target, TOI-904 c 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-904 c is an epic exoplanet

TOI-904 c scores 50 points on Spacedle's rarity scale, which places it in the epic tier. Another 28 points would lift it into a rarer tier.

That score comes from 5 science badges — Confirmed exoplanet, In the habitable zone, Sub-Neptune, 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.