- weight
- 0.97 g
- sun
- 18.3× wider
- sky
- bright white
Illustration computed from this world’s measured and derived values, not a photograph.
HR 858 c
HR 858 c is a confirmed sub-Neptune exoplanet 104 ly from Earth in the constellation Fornax, discovered in 2019 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 HR 858 c, you would weigh almost exactly what you weigh on Earth. Its yellow-white star looks 18.3× wider than ours, bathing the surface in bright 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 6.0 days, and at an estimated 1036°C (1897°F) it is hot enough to melt rock.
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 0.97 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 1036°C (1897°F), sound would travel roughly 113% 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.
- !At about 1036°C (1897°F), the daytime side glows: metals run liquid and any atmosphere is being torn away.
- Surface gravity is close to Earth's, 0.97 times, so you would move much as you do here.
- !Its star delivers about 512 times the sunlight Earth gets, a blinding, sterilizing glare.
- !Earth-similarity index 0.17: 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 HR 858 c’s measured and computed values, not a real advisory.
How long to get there · 104 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 HR 858 c?
HR 858 c's surface gravity is about 0.97 times Earth's.
How much would you weigh on HR 858 c?
Someone who weighs 150 pounds on Earth would weigh about 146 pounds on HR 858 c.
How far is HR 858 c from Earth?
HR 858 c lies about 104 light-years from Earth.
How long would it take to get to HR 858 c?
At the speed of NASA's Parker Solar Probe, the fastest craft ever built, the journey would take about 162,593 years.
How hot is HR 858 c?
HR 858 c's equilibrium temperature, the balance it reaches from its star's light alone before any greenhouse warming, is about 1036°C (1897°F).
How long is a year on HR 858 c?
HR 858 c completes one orbit of its star in 6.0 days.
Illustration generated from HR 858 c's confirmed parameters, not a photograph.