Uncommon exoplanet 25 EP

HD 40307 b

RA 88.5172° · Dec -60.0237° · exoplanet

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Score breakdown

· 3 badges

25 pts · Uncommon

Uncommon 33 pts → Rare

Richly packed system +14
Multi-planet system +6
Confirmed exoplanet +5

Total score 25

8 more points to reach Rare.

Badges

Confirmed exoplanet · +5
Multi-planet system · +6
Richly packed system · +14

Trivia

What makes it special

Packed system. Crammed into a system of five or more planets.

Could we get there?

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

Getting there

Aboard Voyager 1. ≈ 741.4 thousand years at Voyager 1's speed (17 km/s).
Fastest probe ever. ≈ 65.9 thousand years even at the Parker Solar Probe's 192 km/s.
At 10% light speed. ≈ 422 years in a starship at a tenth of light speed.
Distance. 42.2 light-years from Earth.

Look-back time

Look-back time. The light you'd see left around the year 1984.

Saying hello

Say hello. A radio message and its reply would take 84.4 years round-trip.

Standing on it

A year here. A full year lasts just 4.3 Earth days.

By the numbers

Mass. Roughly 1189× Earth's mass — about 3.7 Jupiters.
Temperature. Around 637°C — hotter than a self-cleaning oven.

How we found it

Discovery. Found by La Silla Observatory using the radial velocity method.

Cosmic context

Crowded system. One of at least 5 planets orbiting its star.

Properties

discovery facility: La Silla Observatory
discovery method: Radial Velocity
dist ly: 42.1925
eccentricity: 0.2
eq temp k: 910
insolation: 104.8355
mass earth: 1188.9961
name: HD 40307 b
orbital period days: 4.3123
sys num planets: 5

About HD 40307 b

HD 40307 b is an uncommon exoplanet. It lies about 42.2 light-years from Earth, has an equilibrium temperature near 910 K, weighs about 1,189 Earth masses and completes an orbit every 4.31 days.

Crammed into a system of five or more planets.

How to see it

Like any astronomical target, HD 40307 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 40307 b is an uncommon exoplanet

HD 40307 b scores 25 points on Spacedle's rarity scale, which places it in the uncommon tier. Another 8 points would lift it into a rarer tier.

That score comes from 3 science badges — Confirmed exoplanet, Multi-planet system and Richly packed 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.