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Uncommon exoplanet 29 EP

HD 220842 b

RA 351.6534° · Dec 56.8871° · 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

  • What it is made of. Too light to be solid rock and too heavy to be all gas: most likely a deep global ocean or a thick steamy envelope over a rocky core.

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 September — 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. ≈ 3.7 million years at Voyager 1's speed (17 km/s).
  • Fastest probe ever. ≈ 329.2 thousand years even at the Parker Solar Probe's 192 km/s.

Properties

density gcc
2.47
diameter km
167106.22
discovery facility
Haute-Provence Observatory
discovery method
Radial Velocity
discovery year
2016
dist ly
210.8592
eccentricity
0.404
eq temp k
397.62
host star teff
5960
insolation
4.155
mag
7.98
mass earth
1010.6994
multi star system
yes
name
HD 220842 b
orbital period days
218.47
radius earth
13.1
semi major au
0.74
spect
F8
sys num planets
1
sys num stars
2

About HD 220842 b

HD 220842 b is an uncommon exoplanet. It lies about 210.9 light-years from Earth, shines at apparent magnitude 7.98, has spectral type F8 and has an equilibrium temperature near 398 K.

Too light to be solid rock and too heavy to be all gas: most likely a deep global ocean or a thick steamy envelope over a rocky core.

How to see it

At apparent magnitude 7.98, it is an easy target for binoculars.

Like any astronomical target, HD 220842 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 220842 b is an uncommon exoplanet

HD 220842 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.