Rare exoplanet 33 EP

HD 209458 b

RA 330.7950° · Dec 18.8842° · exoplanet

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Score breakdown

· 4 badges

33 pts · Rare

Rare 46 pts → Epic

Lava world +14
Hot Jupiter +10
Confirmed exoplanet +5
Gas giant +4

Total score 33

13 more points to reach Epic.

Badges

Confirmed exoplanet · +5
Gas giant · +4
Hot Jupiter · +10
Lava world · +14

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. ≈ 2.8 million years at Voyager 1's speed (17 km/s).
Fastest probe ever. ≈ 246 thousand years even at the Parker Solar Probe's 192 km/s.
At 10% light speed. ≈ 1575 years in a starship at a tenth of light speed.
Distance. 158 light-years from Earth.

Look-back time

Look-back time. The light you'd see left around the year 1868.

Saying hello

Say hello. A radio message and its reply would take 315 years round-trip.

Standing on it

A year here. A full year lasts just 3.5 Earth days.

By the numbers

Size. About 15.6× the width of Earth.
Volume. About 3782 Earths could fit inside it.
Mass. Roughly 232× Earth's mass — about 0.7 Jupiters.
Your weight. You'd weigh about 1.0× your Earth weight standing here.
Density. Less dense than water — drop it in a big enough ocean and it would float.
Temperature. Around 1186°C — hotter than a self-cleaning oven.

How we found it

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

Properties

density gcc: 0.362
discovery facility: W. M. Keck Observatory
discovery method: Radial Velocity
dist ly: 157.5386
eccentricity: 0
eq temp k: 1459
insolation: 587.098
mass earth: 232.0159
name: HD 209458 b
orbital period days: 3.5247
radius earth: 15.5805
sys num planets: 1

About HD 209458 b

HD 209458 b is a rare exoplanet. It lies about 157.5 light-years from Earth, has an equilibrium temperature near 1,459 K, spans roughly 15.58 Earth radii and weighs about 232.02 Earth masses.

Its surface is likely an ocean of molten rock.

How to see it

Like any astronomical target, HD 209458 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 209458 b is a rare exoplanet

HD 209458 b scores 33 points on Spacedle's rarity scale, which places it in the rare tier. Another 13 points would lift it into a rarer tier.

That score comes from 4 science badges — Confirmed exoplanet, Gas giant, Hot Jupiter and Lava world — 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.