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Rare exoplanet 35 EP

HD 13931 b

RA 34.1980° · Dec 43.7722° · exoplanet

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Score breakdown

· 5 badges
35 pts · Rare
Rare 50 pts → Epic
  • Long-period world +10
  • Frozen world +8
  • Orbits a Sun-like star +8
  • Confirmed exoplanet +5
  • Gas giant +4
Total score 35

15 more points to reach Epic.

Badges

  • Confirmed exoplanet · +5
  • Gas giant · +4
  • Frozen world · +8
  • Long-period world · +10
  • 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.

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 7.6 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 October — 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. ≈ 2.7 million years at Voyager 1's speed (17 km/s).

Properties

density gcc
2.13
diameter km
168381.84
discovery facility
W. M. Keck Observatory
discovery method
Radial Velocity
discovery year
2009
dist ly
154.5859
eccentricity
0.02
eq temp k
139.38
host star teff
5867
inclination
43
insolation
0.0592
mag
7.61
mass earth
889.9195
name
HD 13931 b
orbital period days
4218
radius earth
13.2
semi major au
5.15
spect
G0
sys num planets
1
sys num stars
1

About HD 13931 b

HD 13931 b is a rare exoplanet. It lies about 154.6 light-years from Earth, shines at apparent magnitude 7.61, has spectral type G0 and has an equilibrium temperature near 139 K.

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

How to see it

At apparent magnitude 7.61, it is an easy target for binoculars.

Like any astronomical target, HD 13931 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 13931 b is a rare exoplanet

HD 13931 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, Frozen world, Long-period world 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.