- weight
- 0.86 g
- sun
- 17.3× wider
- sky
- deep orange
Illustration computed from this world’s measured and derived values, not a photograph.
TOI-663 b
TOI-663 b is a confirmed sub-Neptune exoplanet 209 ly from Earth in the constellation Sextans, discovered in 2024 by Transiting Exoplanet Survey Satellite (TESS).
Transit: spotted by the tiny, repeating dip in its star’s light each time the planet crosses in front of it.
Standing on TOI-663 b, you would weigh about 14% less than you do on Earth. Its red dwarf looks 17.3× wider than ours, bathing the surface in deep orange light. It is likely tidally locked, so that sun never moves in the sky: one hemisphere in endless day, the other in permanent night. A year passes in just 2.6 days, and at an estimated 401°C (754°F) it is blistering.
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
Gravity close to Earth's, at 0.86 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 high and thin, almost cartoonish.
Assuming Earth-like air at this world's temperature of about 401°C (754°F), sound would travel roughly 53% faster than on Earth, so your voice would sound high and thin, almost cartoonish. The real atmosphere is unknown, so this is a best guess.
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.
- !Blistering at about 401°C (754°F), far too hot for liquid water on the surface.
- Surface gravity is close to Earth's, 0.86 times, so you would move much as you do here.
- !Likely tidally locked: one hemisphere in endless day, the other in permanent night.
A playful read of TOI-663 b’s measured and computed values, not a real advisory.
How long to get there · 209 ly away
Zoom out: star → system → (soon) galaxy arm, host black hole, and a real image of the host galaxy.
Matched telescope & eyepiece recommendations are coming. Any product links will carry a clear affiliate disclosure.
What is the gravity on TOI-663 b?
TOI-663 b's surface gravity is about 0.86 times Earth's.
How much would you weigh on TOI-663 b?
Someone who weighs 150 pounds on Earth would weigh about 130 pounds on TOI-663 b.
How far is TOI-663 b from Earth?
TOI-663 b lies about 209 light-years from Earth.
How long would it take to get to TOI-663 b?
At the speed of NASA's Parker Solar Probe, the fastest craft ever built, the journey would take about 326,727 years.
How hot is TOI-663 b?
TOI-663 b's equilibrium temperature, the balance it reaches from its star's light alone before any greenhouse warming, is about 401°C (754°F).
How long is a year on TOI-663 b?
TOI-663 b completes one orbit of its star in 2.6 days.
Illustration generated from TOI-663 b's confirmed parameters, not a photograph.