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Common exoplanet 21 EP

HD 100655 b

RA 173.7654° · Dec 20.4415° · exoplanet

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Score breakdown

· 3 badges
21 pts · Common
Common 22 pts → Uncommon
  • Two suns in its sky +12
  • Confirmed exoplanet +5
  • Gas giant +4
Total score 21

1 more point to reach Uncommon.

Badges

  • Confirmed exoplanet · +5
  • Gas giant · +4
  • Two suns in its sky · +12

Trivia

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 6.4 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 March — that's when to go looking.

Could we get there?

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

Getting there

  • Aboard Voyager 1. ≈ 7.9 million years at Voyager 1's speed (17 km/s).
  • Fastest probe ever. ≈ 698.6 thousand years even at the Parker Solar Probe's 192 km/s.

Properties

density gcc
1.14
diameter km
172208.7
discovery facility
Bohyunsan Optical Astronomical Observatory
discovery method
Radial Velocity
discovery year
2011
dist ly
447.4143
eccentricity
0.09
eq temp k
907.14
host star teff
4891
insolation
92.9931
mag
6.4421
mass earth
511.7063
multi star system
yes
name
HD 100655 b
orbital period days
157.57
radius earth
13.5
semi major au
0.68
spect
G9 III
sys num planets
1
sys num stars
2

About HD 100655 b

HD 100655 b is a common exoplanet. It lies about 447.4 light-years from Earth, shines at apparent magnitude 6.44, has spectral type G9 III and has an equilibrium temperature near 907 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 6.44, it is an easy target for binoculars.

Like any astronomical target, HD 100655 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 100655 b is a common exoplanet

HD 100655 b scores 21 points on Spacedle's rarity scale, which places it in the common tier. Another 1 point would lift it into a rarer tier.

That score comes from 3 science badges — Confirmed exoplanet, Gas giant 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.