Epic exoplanet 60 EP

HD 40307 g

RA 88.5172° · Dec -60.0237° · exoplanet

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Score breakdown

· 5 badges

60 pts · Epic

Epic 68 pts → Anomaly

In the habitable zone +30
Richly packed system +14
Multi-planet system +6
Confirmed exoplanet +5
Sub-Neptune +5

Total score 60

8 more points to reach Anomaly.

Badges

Confirmed exoplanet · +5
In the habitable zone · +30
Sub-Neptune · +5
Multi-planet system · +6
Richly packed system · +14

Trivia

What makes it special

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

By the numbers

Size. About 2.6× the width of Earth.
Volume. About 16.8 Earths could fit inside it.
Mass. About 7.1× the mass of Earth.
Your weight. You'd weigh about 1.1× your Earth weight standing here.
Temperature. A surprisingly temperate -18°C average.

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

density gcc: 2.33
discovery facility: La Silla Observatory
discovery method: Radial Velocity
dist ly: 42.1925
eccentricity: 0.29
eq temp k: 255
habitable zone: yes
insolation: 0.6378
mass earth: 7.1
name: HD 40307 g
orbital period days: 197.8
radius earth: 2.56
sys num planets: 5

About HD 40307 g

HD 40307 g is an epic exoplanet. It lies about 42.2 light-years from Earth, has an equilibrium temperature near 255 K, spans roughly 2.56 Earth radii and weighs about 7.1 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 40307 g 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 g is an epic exoplanet

HD 40307 g scores 60 points on Spacedle's rarity scale, which places it in the epic tier. Another 8 points would lift it into a rarer tier.

That score comes from 5 science badges — Confirmed exoplanet, In the habitable zone, Sub-Neptune, 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.