Rare exoplanet 43 EP

KMT-2021-BLG-1303L b

RA 271.8639° · Dec -29.2816° · exoplanet

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Score breakdown

· 5 badges

43 pts · Rare

Rare 46 pts → Epic

Puffy low-density world +12
Found by microlensing +12
Distant (>1000 ly) +10
Confirmed exoplanet +5
Gas giant +4

Total score 43

3 more points to reach Epic.

Badges

Confirmed exoplanet · +5
Gas giant · +4
Puffy low-density world · +12
Found by microlensing · +12
Distant (>1000 ly) · +10

Trivia

What makes it special

Cotton-candy planet. So low-density it would float on water.

Could we get there?

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

Getting there

Aboard Voyager 1. ≈ 359.9 million years at Voyager 1's speed (17 km/s).
Fastest probe ever. ≈ 32 million years even at the Parker Solar Probe's 192 km/s.
At 10% light speed. ≈ 204.8 thousand years in a starship at a tenth of light speed.
Distance. 20.5 thousand light-years from Earth.

Look-back time

Look-back time. This light set out before Homo sapiens existed.

Saying hello

Say hello. A radio message and its reply would take 41 thousand years round-trip.

By the numbers

Size. About 13.6× the width of Earth.
Volume. About 2515 Earths could fit inside it.
Mass. Roughly 121× Earth's mass — about 0.4 Jupiters.
Your weight. You'd weigh about 0.7× your Earth weight standing here.
Density. Less dense than water — drop it in a big enough ocean and it would float.

How we found it

Discovery. Found by KMTNet using the microlensing method.

Properties

density gcc: 0.264
discovery facility: KMTNet
discovery method: Microlensing
dist ly: 20482.5968
mass earth: 120.7748
name: KMT-2021-BLG-1303L b
radius earth: 13.6
sys num planets: 1

About KMT-2021-BLG-1303L b

KMT-2021-BLG-1303L b is a rare exoplanet. It lies about 20,482.6 light-years from Earth, spans roughly 13.6 Earth radii, weighs about 120.77 Earth masses and belongs to a system of 1 known planets.

So low-density it would float on water.

How to see it

Like any astronomical target, KMT-2021-BLG-1303L 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 KMT-2021-BLG-1303L b is a rare exoplanet

KMT-2021-BLG-1303L b scores 43 points on Spacedle's rarity scale, which places it in the rare tier. Another 3 points would lift it into a rarer tier.

That score comes from 5 science badges — Confirmed exoplanet, Gas giant, Puffy low-density world, Found by microlensing 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.