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Rare exoplanet 37 EP

TOI-791 b

RA 118.4348° · Dec -69.7017° · exoplanet

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Score breakdown

· 6 badges
37 pts · Rare
Rare 50 pts → Epic
  • Puffy low-density world +12
  • Distant (over 1,000 light-years) +6
  • Multi-planet system +6
  • Confirmed exoplanet +5
  • Gas giant +4
  • Found by TESS +4
Total score 37

13 more points to reach Epic.

Badges

  • Confirmed exoplanet · +5
  • Distant (over 1,000 light-years) · +6
  • Gas giant · +4
  • Puffy low-density world · +12
  • 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

  • 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 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 11.1 you'll want a small backyard telescope.
  • 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.
  • Best time of year. It stands highest in the middle of the night around January — 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
0.037
diameter km
141983.1117
discovery facility
Transiting Exoplanet Survey Satellite (TESS)
discovery method
Transit
discovery year
2026
dist ly
1112.9128
eccentricity
0.032
eq temp k
434.3
host star teff
6294
inclination
89.797
insolation
8.47
mag
11.093
mass earth
9.5
name
TOI-791 b
orbital period days
139.2993
radius earth
11.1305
semi major au
0.602
spect
F7
sys num planets
2
sys num stars
1

About TOI-791 b

TOI-791 b is a rare exoplanet. It lies about 1,112.9 light-years from Earth, shines at apparent magnitude 11.09, has spectral type F7 and has an equilibrium temperature near 434 K.

Lighter than Neptune — a puffed-up ball of hydrogen and helium with no surface anywhere on it to stand on.

How to see it

At apparent magnitude 11.09, a small backyard telescope will bring it into view.

Like any astronomical target, TOI-791 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-791 b is a rare exoplanet

TOI-791 b scores 37 points on Spacedle's rarity scale, which places it in the rare tier. Another 13 points would lift it into a rarer tier.

That score comes from 6 science badges — Confirmed exoplanet, Distant (over 1,000 light-years), Gas giant, Puffy low-density world, 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.