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Rare exoplanet 35 EP

HD 217786 b

RA 345.7838° · Dec -0.4304° · exoplanet

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Score breakdown

· 5 badges
35 pts · Rare
Rare 50 pts → Epic
  • Two suns in its sky +12
  • Orbits a Sun-like star +8
  • Multi-planet system +6
  • Confirmed exoplanet +5
  • Gas giant +4
Total score 35

15 more points to reach Epic.

Badges

  • Confirmed exoplanet · +5
  • Gas giant · +4
  • Multi-planet system · +6
  • Orbits a Sun-like star · +8
  • Two suns in its sky · +12

Trivia

Hard to believe

  • Denser than iron. It is packed tighter than solid iron — whatever it is made of, it is not ordinary rock.

What it actually is

  • What it is made of. Denser than Earth — a solid world of rock and iron, with no meaningful atmosphere to speak of by mass.
  • 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 7.8 it is just past naked-eye reach — ordinary binoculars will pull it in.
  • Seen from everywhere. It sits almost on the celestial equator, so it can be seen from essentially anywhere on Earth.
  • Best time of year. It stands highest in the middle of the night around September — that's when to go looking.

Could we get there?

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

Properties

density gcc
13
diameter km
156901.26
discovery facility
La Silla Observatory
discovery method
Radial Velocity
discovery year
2011
dist ly
180.9667
eccentricity
0.311
eq temp k
207.3
host star teff
5966
inclination
69.767
insolation
0.3159
mag
7.78
mass earth
4402.5591
multi star system
yes
name
HD 217786 b
orbital period days
1301.3601
radius earth
12.3
semi major au
2.446
spect
F8 V
sys num planets
2
sys num stars
2

About HD 217786 b

HD 217786 b is a rare exoplanet. It lies about 181 light-years from Earth, shines at apparent magnitude 7.78, has spectral type F8 V and has an equilibrium temperature near 207 K.

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

How to see it

At apparent magnitude 7.78, it is an easy target for binoculars.

Like any astronomical target, HD 217786 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 217786 b is a rare exoplanet

HD 217786 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, Multi-planet system, 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.