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Entering orbit…
Habitability
0/ 100
Uninhabitable
LHS 1678 c rendered in TerraForge from its measured mass, orbit and star

LHS 1678 c

Also written LHS 1678c

Rocky Terrestrial65 light years awayFound 2021
Mass
1.40 × Earth
Radius
0.94 × Earth
Gravity
1.58 g
Surface (est.)
533 K
Year
3.7 days
From Earth
64.9 ly
Mass
1.40 × Earth
Radius
0.94 × Earth
Gravity
1.58 g
Surface (est.)
533 K
Year
3.7 days
From Earth
64.9 ly

LHS 1678 system

Type
M-type (Red Dwarf)
Spectral type
M2.0 V
Temperature
3,490 K
Radius
0.329 ☉
Mass
0.345 ☉
Planets
3
Luminosity
0.0145 ☉

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.

LHS 1678 b0.012 AU0.3 M⊕
LHS 1678 c0.033 AUYou are here1.4 M⊕
LHS 1678 d0.040 AU0.9 M⊕
Habitable zone

Star and planets drawn to scale: the star is 38 times as wide as LHS 1678 c, so only its edge is in view. Orbits spaced as in the star system view.

LHS 1678 c, from the NASA Exoplanet Archive (found 2021). Measured: 1.4 Earth masses, 0.0327 AU, a 3490 K M-type star. Composition inferred from a measured bulk density of 1.68x Earth's, far too high for silicates alone — an iron-rich world, with a day locked to its 3.7-day year, as anything orbiting this close would be.

Surface. Rocky surface with impact craters, possible volcanic features

Rocky Terrestrial
Magnetic FieldModerate Activity
LHS 1678 c is dominated by silicate (36.6%) and iron (24.4%) content, forming a rocky terrestrial body.
Rocky terrestrial planets are primarily composed of silicate rocks and metals. They're the most common type of small planet in the universe.
Classification Criteria:
✓ Silicon: 36.6% + Iron: 24.4% + Magnesium: 12.2%✓ Mass: 1.4x Earth (terrestrial range)

Reading LHS 1678 c’s atmosphere

Dominant elements: Si, Fe, Mg, Ni, S, AlThis is what a telescope would measure while LHS 1678 c 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.LHS 1678 c sits about 65 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.The Little Book of ExoplanetsJoshua WinnHow these worlds are found, and what a measurement can honestly tell us.Exoplanets: Diamond Worlds, Super Earths, Pulsar PlanetsMichael Summers & James TrefilThe strange end of the catalogue — carbon worlds, molten rock, planets orbiting dead stars.
As an Amazon Associate I earn from qualifying purchases — if you buy through these links, TerraForge may receive a small commission at no extra cost to you.
Habitability ScoreUninhabitable
0
Contributing Factors
temperature8
Extremely hot - hostile to known life forms
atmosphere10

Minimal or none

No atmosphere - exposed to radiation and temperature extremes
water0
No water - the recipe has no hydrogen and oxygen to form it
magnetic Field100
Magnetic field provides radiation protection
geology90
Active geology recycles nutrients and drives carbon cycle
Organic Chemistry20
Limited organic chemistry potential
rotation65
Slow rotation - significant day/night temperature variations, but life can adapt

Physical Properties

Mass
1.40x Earth (8.36e+24 kg)
Radius
1.12x Earth (7,127 km)
This planet: 1.12× Earth radiusEarth: 1× (baseline)
Surface Gravity
1.12x Earth (11.0 m/s²)
Surface Temperature
533 K (260 °C / 501 °F)
Rotation Period
88.6 hours/day (slower than Earth)
This planet: 89 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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