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Uncommon exoplanet 23 EP

HIP 10090 c

RA 32.4351° · Dec -30.7471° · exoplanet

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Score breakdown

· 4 badges
23 pts · Uncommon
Uncommon 34 pts → Rare
  • Orbits a Sun-like star +8
  • Multi-planet system +6
  • Confirmed exoplanet +5
  • Gas giant +4
Total score 23

11 more points to reach Rare.

Badges

  • Confirmed exoplanet · +5
  • Gas giant · +4
  • Multi-planet system · +6
  • 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

  • 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 8.9 it is just past naked-eye reach — ordinary binoculars will pull it in.
  • Southern sky. It rides the southern half of the sky — an easier target the further south 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. Hopelessly far for any craft humanity can build today.

Properties

density gcc
0.553
diameter km
177311.18
discovery facility
Multiple Facilities
discovery method
Radial Velocity
discovery year
2026
dist ly
268.732
eccentricity
0.188
eq temp k
338.35
host star teff
5661
inclination
153.8
insolation
1.9857
mag
8.94
mass earth
270.1541
name
HIP 10090 c
orbital period days
321.82
radius earth
13.9
semi major au
0.9
spect
K0
sys num planets
2
sys num stars
1

About HIP 10090 c

HIP 10090 c is an uncommon exoplanet. It lies about 268.7 light-years from Earth, shines at apparent magnitude 8.94, has spectral type K0 and has an equilibrium temperature near 338 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 8.94, it is an easy target for binoculars.

Like any astronomical target, HIP 10090 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 HIP 10090 c is an uncommon exoplanet

HIP 10090 c scores 23 points on Spacedle's rarity scale, which places it in the uncommon tier. Another 11 points would lift it into a rarer tier.

That score comes from 4 science badges — Confirmed exoplanet, Gas giant, Multi-planet system 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.