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Rare exoplanet 39 EP

HD 191939 f

RA 302.0256° · Dec 66.8503° · exoplanet

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Score breakdown

· 5 badges
39 pts · Rare
Rare 50 pts → Epic
  • Richly packed system +14
  • Frozen world +8
  • Orbits a Sun-like star +8
  • Confirmed exoplanet +5
  • Gas giant +4
Total score 39

11 more points to reach Epic.

Badges

  • Confirmed exoplanet · +5
  • Gas giant · +4
  • Frozen world · +8
  • Richly packed system · +14
  • Orbits a Sun-like star · +8

Trivia

What makes it special

  • Frozen world. A deep-frozen world, too far from its star's warmth for anything to stay liquid.

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.
  • Crowded system. One of at least 6 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 9 it is just past naked-eye reach — ordinary binoculars will pull it in.
  • Never sets. So far north that from Britain, Canada or northern Europe it never dips below the horizon — it is up every clear night of the year.
  • 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
2.19
diameter km
168381.84
discovery facility
W. M. Keck Observatory
discovery method
Radial Velocity
discovery year
2022
dist ly
174.8486
eccentricity
0
eq temp k
125
host star teff
5348
insolation
0.0472
mag
8.97
mass earth
915.3458
name
HD 191939 f
orbital period days
2898
radius earth
13.2
semi major au
3.71
spect
G9 V
sys num planets
6
sys num stars
1

About HD 191939 f

HD 191939 f is a rare exoplanet. It lies about 174.8 light-years from Earth, shines at apparent magnitude 8.97, has spectral type G9 V and has an equilibrium temperature near 125 K.

A deep-frozen world, too far from its star's warmth for anything to stay liquid.

How to see it

At apparent magnitude 8.97, it is an easy target for binoculars.

Like any astronomical target, HD 191939 f 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 191939 f is a rare exoplanet

HD 191939 f scores 39 points on Spacedle's rarity scale, which places it in the rare tier. Another 11 points would lift it into a rarer tier.

That score comes from 5 science badges — Confirmed exoplanet, Gas giant, Frozen world, Richly packed system and Orbits a Sun-like star — 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.