- weight
- ≥ 1.05 g
- sun
- 18.1× wider
- sky
- warm white
Illustration computed from this world’s measured and derived values, not a photograph.
HD 39855 b
HD 39855 b is a confirmed sub-Neptune exoplanet 75.9 ly from Earth in the constellation Lepus, discovered in 2019 by Las Campanas Observatory.
Radial Velocity: spotted by the gravitational wobble the planet tugs in its star.
Standing on HD 39855 b, you would weigh roughly about 5% more than you do on Earth. Its yellow, Sun-like star looks 18.1× wider than ours, bathing the surface in warm white 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 3.2 days, and at an estimated 873°C (1603°F) it is furnace-hot.
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 about 1.0 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 873°C (1603°F), sound would travel roughly 99% 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.
- !Furnace-hot at around 873°C (1603°F), with no liquid water and no shade anywhere.
- Surface gravity is close to Earth's, at least 1.05 times, so you would move much as you do here.
- !Its star delivers about 287 times the sunlight Earth gets, a blinding, sterilizing glare.
- !Earth-similarity index 0.18: this world has almost nothing in common with our own.
- !Likely tidally locked: one hemisphere in endless day, the other in permanent night.
A playful read of HD 39855 b’s measured and computed values, not a real advisory.
How long to get there · 75.9 ly away
No other confirmed planets here yet. New ones auto-appear as telescopes report.
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 HD 39855 b?
HD 39855 b's surface gravity is at least 1.0 times Earth's, and possibly more: its mass is only a lower bound.
How much would you weigh on HD 39855 b?
Someone who weighs 150 pounds on Earth would weigh at least 157 pounds on HD 39855 b.
How far is HD 39855 b from Earth?
HD 39855 b lies about 75.9 light-years from Earth.
How long would it take to get to HD 39855 b?
At the speed of NASA's Parker Solar Probe, the fastest craft ever built, the journey would take about 118,317 years.
How hot is HD 39855 b?
HD 39855 b's equilibrium temperature, the balance it reaches from its star's light alone before any greenhouse warming, is about 873°C (1603°F).
How long is a year on HD 39855 b?
HD 39855 b completes one orbit of its star in 3.2 days.
Illustration generated from HD 39855 b's confirmed parameters, not a photograph.