Rare exoplanet 39 EP

HD 187123 b

RA 296.7429° · Dec 34.4190° · exoplanet

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Score breakdown

· 5 badges

39 pts · Rare

Rare 46 pts → Epic

Lava world +14
Hot Jupiter +10
Multi-planet system +6
Confirmed exoplanet +5
Gas giant +4

Total score 39

7 more points to reach Epic.

Badges

Confirmed exoplanet · +5
Gas giant · +4
Hot Jupiter · +10
Lava world · +14
Multi-planet system · +6

Trivia

What makes it special

Lava world. Its surface is likely an ocean of molten rock.

Could we get there?

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

Getting there

Aboard Voyager 1. ≈ 2.6 million years at Voyager 1's speed (17 km/s).
Fastest probe ever. ≈ 234 thousand years even at the Parker Solar Probe's 192 km/s.
At 10% light speed. ≈ 1499 years in a starship at a tenth of light speed.
Distance. 150 light-years from Earth.

Look-back time

Look-back time. The light you'd see left around the year 1876.

Saying hello

Say hello. A radio message and its reply would take 300 years round-trip.

Standing on it

A year here. A full year lasts just 3.1 Earth days.

By the numbers

Size. About 14.2× the width of Earth.
Volume. About 2863 Earths could fit inside it.
Mass. Roughly 166× Earth's mass — about 0.5 Jupiters.
Your weight. You'd weigh about 0.8× your Earth weight standing here.
Density. Less dense than water — drop it in a big enough ocean and it would float.
Temperature. Around 1178°C — hotter than a self-cleaning oven.

How we found it

Discovery. Found by W. M. Keck Observatory using the radial velocity method.

Cosmic context

Crowded system. One of at least 2 planets orbiting its star.

Properties

density gcc: 0.319
discovery facility: W. M. Keck Observatory
discovery method: Radial Velocity
dist ly: 149.8843
eccentricity: 0.0103
eq temp k: 1450.9
insolation: 738.4255
mass earth: 166.218
name: HD 187123 b
orbital period days: 3.0966
radius earth: 14.2
sys num planets: 2

About HD 187123 b

HD 187123 b is a rare exoplanet. It lies about 149.9 light-years from Earth, has an equilibrium temperature near 1,451 K, spans roughly 14.2 Earth radii and weighs about 166.22 Earth masses.

Its surface is likely an ocean of molten rock.

How to see it

Like any astronomical target, HD 187123 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 187123 b is a rare exoplanet

HD 187123 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 5 science badges — Confirmed exoplanet, Gas giant, Hot Jupiter, Lava world and Multi-planet system — 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.