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Entering orbit…
Habitability
72/ 100
Habitable
HIP 41378 d rendered in TerraForge from its measured mass, orbit and star

HIP 41378 d

Also written HIP 41378d

Water-Rich346 light years awayFound 2016
Mass
6.53 × Earth
Radius
3.65 × Earth
Gravity
0.49 g
Surface (est.)
336 K
Year
278 days
From Earth
346 ly
Mass
6.53 × Earth
Radius
3.65 × Earth
Gravity
0.49 g
Surface (est.)
336 K
Year
278 days
From Earth
346 ly

HIP 41378 system

Type
F-type (White)
Spectral type
F6
Temperature
6,290 K
Radius
1.3 ☉
Mass
1.22 ☉
Planets
6
Luminosity
2.49 ☉

Published by the NASA Exoplanet Archive. This world’s temperature and habitability score are computed from this star’s measured luminosity, not from a stand-in for its class.

HIP 41378 b0.13 AU6.9 M⊕
HIP 41378 c0.21 AU6.0 M⊕
HIP 41378 e0.68 AU7.6 M⊕
HIP 41378 d1.17 AUYou are here6.5 M⊕
HIP 41378 f1.39 AU25 M⊕
Habitable zone

Star and planets drawn to scale: the star is 39 times as wide as HIP 41378 d, so only its edge is in view. Orbits spaced as in the star system view.

HIP 41378 d, from the NASA Exoplanet Archive (found 2016). Measured: 6.53 Earth masses, 1.17 AU, a 6290 K F-type star. Composition inferred from a measured bulk density of 0.13x Earth's, larger than even a pure water/ice world of this mass, suggesting a water-rich interior under roughly a 14% hydrogen/helium envelope by mass, with an assumed 24-hour day — rotation cannot be measured for exoplanets.

Surface. Vast oceans covering most of the surface, scattered islands or archipelagos

✓ Conditions could support life. This planet’s modelled conditions could support biological processes: stable temperatures, liquid water and the chemistry life as we know it needs. That makes life possible, not present.

Water-Rich
Life possibleMagnetic FieldExtreme Activity
HIP 41378 d has abundant oxygen (26.7%) and hydrogen (54.9%), creating extensive water coverage while in the habitable temperature zone.
Water worlds have deep global oceans covering most or all of their surface. They form when planets have high water content and orbit in the habitable zone.
Classification Criteria:
✓ Oxygen: 26.7% + Hydrogen: 54.9% (water-forming elements)✓ Temperature: 336K (habitable range)✓ Distance: 1.17 AU (habitable zone)

Reading HIP 41378 d’s atmosphere

Dominant elements: H, O, Si, He, Fe, NThis is what a telescope would measure while HIP 41378 d crosses in front of its star: starlight passes through the atmosphere and spreads into a rainbow band. Each dark line marks a wavelength the atmosphere absorbed.Every element absorbs its own signature wavelengths — hydrogen always darkens the same two spots, calcium another pair, and so on. Astronomers match the lines in a real spectrum against a library of these signatures to say what an atmosphere is made of, light-years away, without ever visiting. A deeper line generally means more of that element is present.HIP 41378 d sits about 346 light-years away, found by the transit method. Most catalogued distances trace back to parallax: as Earth orbits the Sun, a nearby star appears to shift very slightly against the distant background stars, and the size of that shift gives its distance directly.
Further reading
ExoplanetsSara Seager (editor)The field's standard reference: how planets are found, how they form, and what their atmospheres are made of.The Planet FactoryElizabeth TaskerHow planets are made, and why so few of them come out like Earth.Imagined LifeJames Trefil & Michael SummersWhat could live on a world like this one: ice shells, supergravity, tidally locked twilight.Envisioning ExoplanetsMichael CarrollWhat these worlds might look like from the ground, painted from the same measurements this page renders.
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Habitability ScoreHabitable
72
Contributing Factors
temperature48
Warm - livable, but heat stress grows with every degree
atmosphere100

Nitrogen and oxygen with water vapor, mild greenhouse effect

Nitrogen-oxygen atmosphere - breathable and protective
water100
Abundant water
magnetic Field100
Magnetic field provides radiation protection
geology40
Extreme volcanic activity may be hazardous
Organic Chemistry80
Core organic elements (CHNO) present
rotation100
Optimal rotation period - balanced day/night cycle, moderate weather, and good heat distribution

Physical Properties

Mass
6.53x Earth (3.90e+25 kg)
Radius
1.87x Earth (11,908 km)
This planet: 1.87× Earth radiusEarth: 1× (baseline)
Surface Gravity
1.87x Earth (18.3 m/s²)
Surface Temperature
336 K (63 °C / 145 °F)
Rotation Period
24.0 hours/day
This planet: 24 h/dayEarth: 24 h/day

Elemental Composition

A dark ringed planet hanging over the horizon of a rocky moon, its rings lit by a distant sun

New: Stand on Your Moons 🌒

A planet's surface view isn't the only ground any more. Press the surface button on a planet with moons and it asks where to stand: the planet itself, or any moon still in orbit, each tagged with what it became — ocean, ice, carbon, volcanic. Every moon gets its own ground and sky from its own physics: airless rock under a black sky, ice cracked by geysers over a hidden sea, sulfur plains shaking with eruptions, or orange haze you can't see the sun through. And hanging over the horizon, there's the planet you built.

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