Uncommon exoplanet 32 EP

Kepler-399 d

RA 299.5017° · Dec 40.6708° · exoplanet

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Score breakdown

· 5 badges

32 pts · Uncommon

Uncommon 33 pts → Rare

Distant (>1000 ly) +10
Super-Earth +8
Multi-planet system +6
Confirmed exoplanet +5
Found by Kepler +3

Total score 32

1 more point to reach Rare.

Badges

Confirmed exoplanet · +5
Super-Earth · +8
Multi-planet system · +6
Found by Kepler · +3
Distant (>1000 ly) · +10

Trivia

Could we get there?

Verdict. Impossible with our current technology — and the next millennium of it.

Getting there

Aboard Voyager 1. ≈ 42.4 million years at Voyager 1's speed (17 km/s).
Fastest probe ever. ≈ 3.8 million years even at the Parker Solar Probe's 192 km/s.
At 10% light speed. ≈ 24.2 thousand years in a starship at a tenth of light speed.
Distance. 2415 light-years from Earth.

Look-back time

Look-back time. Its light left before the last ice age ended.

Saying hello

Say hello. A radio message and its reply would take 4831 years round-trip.

Standing on it

A year here. A full year lasts just 58 Earth days.

By the numbers

Size. About 1.9× the width of Earth.
Volume. About 6.8 Earths could fit inside it.
Mass. About 4.2× the mass of Earth.
Your weight. You'd weigh about 1.2× your Earth weight standing here.
Temperature. A scorching 213°C on average.

How we found it

Discovery. Found by Kepler using the transit method.

Cosmic context

Crowded system. One of at least 3 planets orbiting its star.

Properties

density gcc: 3.44
discovery facility: Kepler
discovery method: Transit
dist ly: 2415.3059
eccentricity: 0
eq temp k: 486
insolation: 5.57
mass earth: 4.23
name: Kepler-399 d
orbital period days: 58.0346
radius earth: 1.89
sys num planets: 3

About Kepler-399 d

Kepler-399 d is an uncommon exoplanet. It lies about 2,415.3 light-years from Earth, has an equilibrium temperature near 486 K, spans roughly 1.89 Earth radii and weighs about 4.23 Earth masses.

One of at least 3 planets orbiting its star.

How to see it

Like any astronomical target, Kepler-399 d 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 Kepler-399 d is an uncommon exoplanet

Kepler-399 d scores 32 points on Spacedle's rarity scale, which places it in the uncommon tier. Another 1 point would lift it into a rarer tier.

That score comes from 5 science badges — Confirmed exoplanet, Super-Earth, Multi-planet system, Found by Kepler and Distant (>1000 ly) — 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.