What it’s like to stand here
BD+15 2940 b
weight
≥ 1.88 g
sun
27.1× wider
sky
amber-orange

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

BD+15 2940 b

BD+15 2940 b is a confirmed gas-giant exoplanet 1,391 ly from Earth in the constellation Serpens, discovered in 2013 by McDonald Observatory.

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

BD+15 2940
host star
13.70 R⊕
radius
353 M⊕
mass · minimum (m·sin i)
137 days
orbital period
935°C (1714°F)
avg temp
Human scale

BD+15 2940 b is a giant ball of gas with no solid surface to stand on; you would simply sink into ever-thicker cloud. Its orange dwarf looks 27.1× wider than ours, bathing the cloud tops in amber-orange light. A year passes in just 137 days, and at an estimated 935°C (1714°F) it is hot enough to melt rock.

≥ 1.88 g
surface gravity (no solid surface · minimum mass only)
137 days
one year, in Earth time
27.1× wider
how big its sun looks vs ours
amber-orange
midday sky tint
0.5×
how high you could jump vs Earth
normal
day/night cycle (not tidally locked)
Calculate your exact weight on BD+15 2940 b
Earth Similarity Index0.10#5,102 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
NO GROUND: A DRIFTER, NOT A WALKER

There is no ground here to grow up on, only bottomless sky. A child could never stand, walk, or even fall to a surface, because there isn't one. Under about 1.9 times Earth's gravity and pressure that only climbs the deeper you go, anything built for this world would not look human at all: picture something closer to a deep-sea creature than a person, broad and buoyant, drifting through the cloud decks with no need for legs and no floor to land on.

Body plan
Floating, not upright
With no surface and no fixed up or down, a skeleton built for standing would be useless; a drifting, gas-filled body would not.
Build
Broad and pressure-hardened
Pressure rises without limit toward the interior, so anything alive would have to be built like a deep-sea animal, not a land one.

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 a thin, helium-fast squeak.

There is no surface to stand on; this is the sound at the cloud tops, where the air is mostly hydrogen and helium, the lightest gases there are. Sound races through them at about 2,472 metres per second, 7.3 times its Earth speed, flipping a voice into a thin, cartoon-helium squeak. The temperature behind that number is this world's computed equilibrium temperature; its real atmosphere is unknown. The demo plays the shift capped at 1.8x; the real effect would be even stronger.

sound speed ≈ 2472 m/s · 7.27× Earth

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
☆☆☆☆
Do not travel
  • !At about 935°C (1714°F), the daytime side glows: metals run liquid and any atmosphere is being torn away.
  • !There is nowhere to land: no ground, no deck, only cloud that thickens into crushing pressure.
  • !Its star delivers about 352 times the sunlight Earth gets, a blinding, sterilizing glare.
  • !Earth-similarity index 0.10: this world has almost nothing in common with our own.

A playful read of BD+15 2940 b’s measured and computed values, not a real advisory.

How long to get there · 1,391 ly away
Jet airliner
1.7 billion years
dies en route1000-yr cryo: fails
Parker Solar Probethe fastest craft ever built
2.2 million years
dies en route1000-yr cryo: fails
Light speed
1,391 years
dies en route1000-yr cryo: fails
Warp 10
1 year
arrives, just older
Folding spacetimeinstant, plus 1 hr of paperwork
1 hour
arrives thriving
Size vs Earth
EarthBD+15 2940 b is 14× 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 9.0
ConstellationSerpens
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 BD+15 2940 b?

BD+15 2940 b is a gas giant with no solid surface to stand on. At its cloud tops, gravity pulls at least 1.9 times as hard as Earth's.

How far is BD+15 2940 b from Earth?

BD+15 2940 b lies about 1,391 light-years from Earth.

How long would it take to get to BD+15 2940 b?

At the speed of NASA's Parker Solar Probe, the fastest craft ever built, the journey would take about 2.2 million years.

How hot is BD+15 2940 b?

BD+15 2940 b's equilibrium temperature, the balance it reaches from its star's light alone before any greenhouse warming, is about 935°C (1714°F).

How long is a year on BD+15 2940 b?

BD+15 2940 b completes one orbit of its star in 137 days.

Illustration generated from BD+15 2940 b's confirmed parameters, not a photograph.