Epic exoplanet 52 EP

HN Lib b

RA 218.5685° · Dec -12.5170° · exoplanet

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Score breakdown

· 4 badges

52 pts · Epic

Epic 68 pts → Anomaly

In the habitable zone +30
Nearby (<25 ly) +12
Confirmed exoplanet +5
Sub-Neptune +5

Total score 52

16 more points to reach Anomaly.

Badges

Confirmed exoplanet · +5
In the habitable zone · +30
Sub-Neptune · +5
Nearby (<25 ly) · +12

Trivia

What makes it special

Goldilocks zone. Sits where it's neither too hot nor too cold — liquid water could exist.

Could we get there?

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

Getting there

Aboard Voyager 1. ≈ 357.9 thousand years at Voyager 1's speed (17 km/s).
Fastest probe ever. ≈ 31.8 thousand years even at the Parker Solar Probe's 192 km/s.
At 10% light speed. ≈ 204 years in a starship at a tenth of light speed.
Distance. 20.4 light-years from Earth.

Look-back time

Look-back time. The light you'd see left around the year 2006.

Saying hello

Say hello. A radio message and its reply would take 40.7 years round-trip.

Standing on it

A year here. A full year lasts just 36.1 Earth days.

By the numbers

Size. About 2.2× the width of Earth.
Volume. About 10.6 Earths could fit inside it.
Mass. About 5.5× the mass of Earth.
Your weight. You'd weigh about 1.1× your Earth weight standing here.
Temperature. A frigid -39°C — colder than dry ice.

How we found it

Discovery. Found by Calar Alto Observatory using the radial velocity method.

Properties

density gcc: 2.82
discovery facility: Calar Alto Observatory
discovery method: Radial Velocity
dist ly: 20.3666
eccentricity: 0.079
eq temp k: 234.4
habitable zone: yes
insolation: 0.503
mass earth: 5.46
name: HN Lib b
orbital period days: 36.116
radius earth: 2.2
sys num planets: 1

About HN Lib b

HN Lib b is an epic exoplanet. It lies about 20.4 light-years from Earth, has an equilibrium temperature near 234 K, spans roughly 2.2 Earth radii and weighs about 5.46 Earth masses.

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

How to see it

Like any astronomical target, HN Lib 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 HN Lib b is an epic exoplanet

HN Lib b scores 52 points on Spacedle's rarity scale, which places it in the epic tier. Another 16 points would lift it into a rarer tier.

That score comes from 4 science badges — Confirmed exoplanet, In the habitable zone, Sub-Neptune and Nearby (<25 ly) — 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.