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Rare exoplanet 47 EP

HD 103891 b

RA 179.4383° · Dec -8.5486° · exoplanet

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Score breakdown

· 4 badges
47 pts · Rare
Rare 50 pts → Epic
  • In the habitable zone +30
  • Orbits a Sun-like star +8
  • Confirmed exoplanet +5
  • Gas giant +4
Total score 47

3 more points to reach Epic.

Badges

  • Confirmed exoplanet · +5
  • In the habitable zone · +30
  • Gas giant · +4
  • Orbits a Sun-like star · +8

Trivia

What makes it special

  • Goldilocks zone. Sits where it's neither too hot nor too cold — liquid water could exist on a surface here.

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.
  • What the zone means. The habitable zone is only about temperature: it is the band where liquid water could survive on a surface. It is a promising address, not evidence of anything living.

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 6.6 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 March — 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
La Silla Observatory
discovery method
Radial Velocity
discovery year
2022
dist ly
181.0861
eccentricity
0.31
eq temp k
241.25
habitable zone
yes
host star teff
6072
inclination
27.4
insolation
0.5714
mag
6.5945
mass earth
918.5241
name
HD 103891 b
orbital period days
1919
radius earth
13.2
semi major au
3.27
spect
F9
sys num planets
1
sys num stars
1

About HD 103891 b

HD 103891 b is a rare exoplanet. It lies about 181.1 light-years from Earth, shines at apparent magnitude 6.59, has spectral type F9 and has an equilibrium temperature near 241 K.

Sits where it's neither too hot nor too cold — liquid water could exist on a surface here.

How to see it

At apparent magnitude 6.59, it is an easy target for binoculars.

Like any astronomical target, HD 103891 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 103891 b is a rare exoplanet

HD 103891 b scores 47 points on Spacedle's rarity scale, which places it in the rare tier. Another 3 points would lift it into a rarer tier.

That score comes from 4 science badges — Confirmed exoplanet, In the habitable zone, Gas giant 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.