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Uncommon exoplanet 29 EP

HD 178911 B b

RA 287.2632° · Dec 34.6007° · exoplanet

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Score breakdown

· 4 badges
29 pts · Uncommon
Uncommon 34 pts → Rare
  • Two suns in its sky +12
  • Orbits a Sun-like star +8
  • Confirmed exoplanet +5
  • Gas giant +4
Total score 29

5 more points to reach Rare.

Badges

  • Confirmed exoplanet · +5
  • Gas giant · +4
  • Orbits a Sun-like star · +8
  • Two suns in its sky · +12

Trivia

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. Denser than Earth — a solid world of rock and iron, with no meaningful atmosphere to speak of by mass.

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 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.

Getting there

  • Aboard Voyager 1. ≈ 2.3 million years at Voyager 1's speed (17 km/s).

Properties

density gcc
7.01
diameter km
160728.12
discovery facility
W. M. Keck Observatory
discovery method
Radial Velocity
discovery year
2001
dist ly
133.6349
eccentricity
0.11
eq temp k
480.24
host star teff
5588
insolation
7.8319
mag
7.97
mass earth
2552.1749
multi star system
yes
name
HD 178911 B b
orbital period days
71.484
radius earth
12.6
semi major au
0.34
spect
G5
sys num planets
1
sys num stars
3

About HD 178911 B b

HD 178911 B b is an uncommon exoplanet. It lies about 133.6 light-years from Earth, shines at apparent magnitude 7.97, has spectral type G5 and has an equilibrium temperature near 480 K.

It orbits closer to its star than Mercury does to the Sun, completing a lap in less time than Mercury takes.

How to see it

At apparent magnitude 7.97, it is an easy target for binoculars.

Like any astronomical target, HD 178911 B 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 178911 B b is an uncommon exoplanet

HD 178911 B b scores 29 points on Spacedle's rarity scale, which places it in the uncommon tier. Another 5 points would lift it into a rarer tier.

That score comes from 4 science badges — Confirmed exoplanet, Gas giant, Orbits a Sun-like star 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.