Rare exoplanet 39 EP

HD 135872 b

RA 229.4214° · Dec -5.2025° · exoplanet

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Score breakdown

· 3 badges

39 pts · Rare

Rare 46 pts → Epic

In the habitable zone +30
Confirmed exoplanet +5
Gas giant +4

Total score 39

7 more points to reach Epic.

Badges

Confirmed exoplanet · +5
In the habitable zone · +30
Gas giant · +4

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. ≈ 4.7 million years at Voyager 1's speed (17 km/s).
Fastest probe ever. ≈ 419.8 thousand years even at the Parker Solar Probe's 192 km/s.
At 10% light speed. ≈ 2688 years in a starship at a tenth of light speed.
Distance. 269 light-years from Earth.

Look-back time

Look-back time. The light you'd see left around the year 1757.

Saying hello

Say hello. A radio message and its reply would take 538 years round-trip.

Standing on it

A year here. A full year lasts about 6.6 Earth years.

By the numbers

Size. About 12.8× the width of Earth.
Volume. About 2097 Earths could fit inside it.
Mass. Roughly 1745× Earth's mass — about 5.5 Jupiters.
Your weight. You'd weigh about 10.6× your Earth weight standing here.
Temperature. A frigid -40°C — colder than dry ice.

How we found it

Discovery. Found by Multiple Observatories using the radial velocity method.

Properties

density gcc: 4.57
discovery facility: Multiple Observatories
discovery method: Radial Velocity
dist ly: 268.8344
eccentricity: 0.164
eq temp k: 233.64
habitable zone: yes
insolation: 0.4969
mass earth: 1744.5601
name: HD 135872 b
orbital period days: 2422.326
radius earth: 12.8
sys num planets: 1

About HD 135872 b

HD 135872 b is a rare exoplanet. It lies about 268.8 light-years from Earth, has an equilibrium temperature near 234 K, spans roughly 12.8 Earth radii and weighs about 1,744.56 Earth masses.

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

How to see it

Like any astronomical target, HD 135872 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 135872 b is a rare exoplanet

HD 135872 b scores 39 points on Spacedle's rarity scale, which places it in the rare tier. Another 7 points would lift it into a rarer tier.

That score comes from 3 science badges — Confirmed exoplanet, In the habitable zone and Gas giant — 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.