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Rare exoplanet 45 EP

TOI-1199 b

RA 166.8807° · Dec 61.3526° · exoplanet

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Score breakdown

· 6 badges
45 pts · Rare
Rare 50 pts → Epic
  • Lava world +14
  • Tidally locked +10
  • Orbits a Sun-like star +8
  • Confirmed exoplanet +5
  • Gas giant +4
  • Found by TESS +4
Total score 45

5 more points to reach Epic.

Badges

  • Confirmed exoplanet · +5
  • Gas giant · +4
  • Lava world · +14
  • Tidally locked · +10
  • Found by TESS · +4
  • Orbits a Sun-like star · +8

Trivia

What makes it special

  • Lava world. Its surface is almost certainly an ocean of molten rock, kept liquid by the star it hugs.

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 11.1 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 March — that's when to go looking.

Properties

density gcc
0.358
diameter km
134118.9917
discovery facility
Transiting Exoplanet Survey Satellite (TESS)
discovery method
Transit
discovery year
2024
dist ly
810.2596
eccentricity
0.03
eq temp k
1486
host star teff
5710
insolation
324.114
mag
11.093
mass earth
75.961
name
TOI-1199 b
orbital period days
3.6715
radius earth
10.514
semi major au
0.0499
sys num planets
1
sys num stars
1
tidally locked
yes
tidally locked inferred
yes

About TOI-1199 b

TOI-1199 b is a rare exoplanet. It lies about 810.3 light-years from Earth, shines at apparent magnitude 11.09, has an equilibrium temperature near 1,486 K and spans roughly 10.51 Earth radii.

Its surface is almost certainly an ocean of molten rock, kept liquid by the star it hugs.

How to see it

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

Like any astronomical target, TOI-1199 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-1199 b is a rare exoplanet

TOI-1199 b scores 45 points on Spacedle's rarity scale, which places it in the rare tier. Another 5 points would lift it into a rarer tier.

That score comes from 6 science badges — Confirmed exoplanet, Gas giant, Lava world, Tidally locked, 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.