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Epic exoplanet 59 EP

TOI-3664 b

RA 35.3085° · Dec 59.7119° · exoplanet

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Score breakdown

· 8 badges
59 pts · Epic
Epic 78 pts → Anomaly
  • Puffy low-density world +12
  • Hot Jupiter +10
  • Tidally locked +10
  • Orbits a Sun-like star +8
  • Distant (over 1,000 light-years) +6
  • Confirmed exoplanet +5
  • Gas giant +4
  • Found by TESS +4
Total score 59

19 more points to reach Anomaly.

Badges

  • Confirmed exoplanet · +5
  • Distant (over 1,000 light-years) · +6
  • Gas giant · +4
  • Hot Jupiter · +10
  • Tidally locked · +10
  • Puffy low-density world · +12
  • Found by TESS · +4
  • Orbits a Sun-like star · +8

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 13.9 it is far too faint for the eye: this one belongs to cameras and long exposures.
  • Northern sky. It rides the northern half of the sky — an easier target the further north you are.
  • Best time of year. It stands highest in the middle of the night around October — that's when to go looking.

Could we get there?

  • Verdict. Impossible with our current technology — and the next millennium of it.

Properties

density gcc
0.248
diameter km
174726.4476
discovery facility
Transiting Exoplanet Survey Satellite (TESS)
discovery method
Transit
discovery year
2026
dist ly
1515.8035
eccentricity
0.159
eq temp k
1232
host star teff
5593
inclination
87.8
insolation
349.544
mag
13.883
mass earth
114.4182
name
TOI-3664 b
orbital period days
3.2975
radius earth
13.6974
semi major au
0.0431
sys num planets
1
sys num stars
1
tidally locked
yes
tidally locked inferred
yes

About TOI-3664 b

TOI-3664 b is an epic exoplanet. It lies about 1,515.8 light-years from Earth, shines at apparent magnitude 13.88, has an equilibrium temperature near 1,232 K and spans roughly 13.7 Earth radii.

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

Like any astronomical target, TOI-3664 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-3664 b is an epic exoplanet

TOI-3664 b scores 59 points on Spacedle's rarity scale, which places it in the epic tier. Another 19 points would lift it into a rarer tier.

That score comes from 8 science badges — Confirmed exoplanet, Distant (over 1,000 light-years), Gas giant, Hot Jupiter, Tidally locked, Puffy low-density world, Found by TESS and Orbits a Sun-like star — 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.