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Uncommon exoplanet 27 EP

HD 177830 c

RA 286.3364° · Dec 25.9204° · exoplanet

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Score breakdown

· 4 badges
27 pts · Uncommon
Uncommon 34 pts → Rare
  • Two suns in its sky +12
  • Multi-planet system +6
  • Confirmed exoplanet +5
  • Gas giant +4
Total score 27

7 more points to reach Rare.

Badges

  • Confirmed exoplanet · +5
  • Gas giant · +4
  • Multi-planet system · +6
  • Two suns in its sky · +12

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

Could we get there?

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

Properties

density gcc
0.537
diameter km
100391.294
discovery facility
W. M. Keck Observatory
discovery method
Radial Velocity
discovery year
2010
dist ly
204.7196
eccentricity
0.3
eq temp k
538.95
host star teff
4949
insolation
18.3487
mag
7.18
mass earth
47.6725
multi star system
yes
name
HD 177830 c
orbital period days
110.9
radius earth
7.87
semi major au
0.5137
spect
K0
sys num planets
2
sys num stars
2

Nearby objects

About HD 177830 c

HD 177830 c is an uncommon exoplanet. It lies about 204.7 light-years from Earth, shines at apparent magnitude 7.18, has spectral type K0 and has an equilibrium temperature near 539 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 7.18, it is an easy target for binoculars.

Like any astronomical target, HD 177830 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 HD 177830 c is an uncommon exoplanet

HD 177830 c scores 27 points on Spacedle's rarity scale, which places it in the uncommon tier. Another 7 points would lift it into a rarer tier.

That score comes from 4 science badges — Confirmed exoplanet, Gas giant, Multi-planet system and Two suns in its sky — 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.