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Rare exoplanet 35 EP

HD 100508 b

RA 173.3014° · Dec -67.0546° · exoplanet

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Score breakdown

· 5 badges
35 pts · Rare
Rare 50 pts → Epic
  • Long-period world +10
  • Frozen world +8
  • Orbits a Sun-like star +8
  • Confirmed exoplanet +5
  • Gas giant +4
Total score 35

15 more points to reach Epic.

Badges

  • Confirmed exoplanet · +5
  • Gas giant · +4
  • Frozen world · +8
  • Long-period world · +10
  • Orbits a Sun-like star · +8

Trivia

What makes it special

  • Frozen world. A deep-frozen world, too far from its star's warmth for anything to stay liquid.

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.

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 7.7 it is just past naked-eye reach — ordinary binoculars will pull it in.
  • 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 March — that's when to go looking.

Could we get there?

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

Properties

density gcc
0.815
diameter km
174759.94
discovery facility
Las Campanas Observatory
discovery method
Radial Velocity
discovery year
2026
dist ly
106.8317
eccentricity
0.42
eq temp k
106.66
host star teff
5419
inclination
62
insolation
0.0216
mag
7.74
mass earth
381.3941
name
HD 100508 b
orbital period days
5681
radius earth
13.7
semi major au
6.11
spect
K1 IV
sys num planets
1
sys num stars
1

About HD 100508 b

HD 100508 b is a rare exoplanet. It lies about 106.8 light-years from Earth, shines at apparent magnitude 7.74, has spectral type K1 IV and has an equilibrium temperature near 107 K.

A deep-frozen world, too far from its star's warmth for anything to stay liquid.

How to see it

At apparent magnitude 7.74, it is an easy target for binoculars.

Like any astronomical target, HD 100508 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 HD 100508 b is a rare exoplanet

HD 100508 b scores 35 points on Spacedle's rarity scale, which places it in the rare tier. Another 15 points would lift it into a rarer tier.

That score comes from 5 science badges — Confirmed exoplanet, Gas giant, Frozen world, Long-period world 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.