What it’s like to stand here
Kapteyn c
weight
≥ 1.09 g
sun
about the same
sky
deep orange

Illustration computed from this world’s measured and derived values, not a photograph.

Kapteyn c

Kapteyn c is a confirmed sub-Neptune exoplanet 12.8 ly from Earth in the constellation Pictor, discovered in 2014 by Multiple Observatories.

ESI 0.5512.8 lyDiscovered in 2014 by Multiple ObservatoriesDisputed detection

Radial Velocity: spotted by the gravitational wobble the planet tugs in its star.

Kapteyn
host star
2.54 R⊕
radius
7.00 M⊕
mass · minimum (m·sin i)
122 days
orbital period
-108°C (-162°F)
avg temp
Human scale

Standing on Kapteyn c, you would weigh roughly about 9% more than you do on Earth. Its red dwarf looks about the same size as ours, bathing the surface in deep orange light. A year passes in just 122 days, and at an estimated -108°C (-162°F) it is deeply frozen.

≥ 1.09 g
your weight (minimum mass only)
122 days
one year, in Earth time
about the same
how big its sun looks vs ours
deep orange
midday sky tint
0.9×
how high you could jump vs Earth
normal
day/night cycle (not tidally locked)
Calculate your exact weight on Kapteyn c
Earth Similarity Index0.55#432 of 5,788 ranked worlds

How closely this world matches Earth in size and warmth, from 0 to 1 (Earth = 1.0). Computed by gravityfinder. See every world ranked →

What these mean: surface gravity · tidal locking · equilibrium temperature · Earth similarity

If your children grew up herea playful thought experiment
EARTH HEIGHT≈ 0.98xEARTH-RAISEDRAISED HERE
much like Earth height

Gravity close to Earth's, at about 1.1 times. A child would grow up much as they would back home.

A playful thought experiment from this world’s gravity, not a prediction about any real person. No human has ever grown up off Earth, so no one truly knows; the direction (taller in low gravity, shorter and stockier in high) follows how growing bodies respond to weight.

Hear how a voice sounds herea computed acoustic demo

Your voice would sound deeper and fuller.

Assuming Earth-like air at this world's temperature of about -108°C (-162°F), sound would travel roughly 24% slower than on Earth, so your voice would sound deeper and fuller. The real atmosphere is unknown, so this is a best guess.

sound speed ≈ 258 m/s · 0.76× Earth · assumes Earth-like air

A real voice sample, pitch-shifted (tempo held constant) to suggest the acoustics: a playful approximation, not a precise simulation. Voice: Lingua Libre / Vealhurl, CC BY-SA 4.0.

The journey
Cosmic travel advisory
★★☆☆☆
Reconsider travel
  • !Deeply frozen at around -108°C (-162°F), far below the freezing point of water.
  • Surface gravity is close to Earth's, at least 1.09 times, so you would move much as you do here.

A playful read of Kapteyn c’s measured and computed values, not a real advisory.

How long to get there · 12.8 ly away
Jet airliner
15.4 million years
dies en route1000-yr cryo: fails
Parker Solar Probethe fastest craft ever built
20,006 years
dies en route1000-yr cryo: fails
Light speed
13 years
arrives middle-aged
Warp 10
5 days
arrives thriving
Folding spacetimeinstant, plus 1 hr of paperwork
1 hour
arrives thriving
Size vs Earth
EarthKapteyn c is 2.5× the width of Earth
Explore from here · roam the neighborhood

Zoom out: star → system → (soon) galaxy arm, host black hole, and a real image of the host galaxy.

Can you see it tonight? · observe
BINOCULARS NEEDED
Host-star brightnessmag 8.9
ConstellationPictor
To see the host star50 mm binoculars
Gear bridge

Matched telescope & eyepiece recommendations are coming. Any product links will carry a clear affiliate disclosure.

Common questions

What is the gravity on Kapteyn c?

Kapteyn c's surface gravity is at least 1.1 times Earth's, and possibly more: its mass is only a lower bound.

How much would you weigh on Kapteyn c?

Someone who weighs 150 pounds on Earth would weigh at least 163 pounds on Kapteyn c.

How far is Kapteyn c from Earth?

Kapteyn c lies about 12.8 light-years from Earth.

How long would it take to get to Kapteyn c?

At the speed of NASA's Parker Solar Probe, the fastest craft ever built, the journey would take about 20,006 years.

How hot is Kapteyn c?

Kapteyn c's equilibrium temperature, the balance it reaches from its star's light alone before any greenhouse warming, is about -108°C (-162°F).

How long is a year on Kapteyn c?

Kapteyn c completes one orbit of its star in 122 days.

Illustration generated from Kapteyn c's confirmed parameters, not a photograph.