Create your free account

Enter your email and we'll send a 6-digit code — no password needed.
We only keep your email and the username you choose. We never share or sell your email, and we don't send marketing — we use it only to email you a sign-in code. Read our privacy policy.
Entering orbit…
Habitability
14/ 100
Uninhabitable
KMT-2025-BLG-0811 b rendered in TerraForge from its measured mass, orbit and star

KMT-2025-BLG-0811 b

Also written KMT-2025-BLG-0811b, KMT 2025 BLG 0811b, KMT 2025 BLG 0811 b

Sub-NeptuneUninhabitable22787 light years awayFound 2026
exoplanet.euListed by the Extrasolar Planets Encyclopaedia; not yet in NASA's confirmed catalogue.View on exoplanet.eu

Estimated: this planet doesn't transit its star, so its size is inferred, not measured

KMT-2025-BLG-0811 b, from the Extrasolar Planets Encyclopaedia (found 2026). Measured: 6.99 Earth masses, 2.47 AU, a 3200 K M-type star. Composition inferred from a estimated bulk density of 0.43x Earth's, modeled rather than measured since this isn't a transiting planet, too low for bare rock at this size, suggesting a rocky core under roughly a 5% hydrogen/helium envelope by mass, with an assumed 24-hour day — rotation cannot be measured for exoplanets.

Host star

KMT-2025-BLG-0811

Type
M-type (Red Dwarf)
Spectral type
M2V
Temperature
3,200 K
Mass
0.49 ☉
Known planets
1 (this one)

Published by the Extrasolar Planets Encyclopaedia. This star’s luminosity has not been published, so this world’s temperature and habitability score fall back to a typical M-type star.

Gas Dwarf

Life unlikely — too cold for liquid waterMagnetic FieldLow Activity
Why is this a Gas Dwarf?
KMT-2025-BLG-0811 b has an unusual composition that doesn't fit standard classifications, or lacks the elements needed for complex geological processes.
Barren worlds can form from uncommon element combinations or may be remnants of larger bodies that lost their atmospheres and volatile materials.
Classification Criteria:
Composition doesn't match standard planet typesMass: 7.0x EarthTemperature: 80K

Reading KMT-2025-BLG-0811 b’s atmosphere

Dominant elements: O, Si, Fe, N, C, HThis is what a telescope would measure while KMT-2025-BLG-0811 b 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.KMT-2025-BLG-0811 b sits about 22799 light-years away, found by the microlensing 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.Exoplanets: Diamond Worlds, Super Earths, Pulsar PlanetsMichael Summers & James TrefilThe strange end of the catalogue — carbon worlds, molten rock, planets orbiting dead stars.The Little Book of ExoplanetsJoshua WinnHow these worlds are found, and what a measurement can honestly tell us.
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
14
Contributing Factors
temperature10
Frozen world - minimal potential for complex life
atmosphere30
Hydrogen-rich atmosphere typical of gas giants
water15
No solid surface — any water is locked in a supercritical mantle and hot ice, not oceans
magnetic Field100
Magnetic field provides radiation protection
geology60
Some geological activity provides slow nutrient cycling
Organic Chemistry80
Core organic elements (CHNO) present
rotation100
Optimal rotation period - balanced day/night cycle, moderate weather, and good heat distribution

Physical Properties

Mass
6.99x Earth (4.17e+25 kg)
Radius
1.91x Earth (12,181 km)
This planet: 1.91× Earth radiusEarth: 1× (baseline)
Surface Gravity
1.91x Earth (18.8 m/s²)
Surface Temperature
80 K (-193 °C / -315 °F)
Rotation Period
24.0 hours/day
This planet: 24 h/dayEarth: 24 h/day

Orbital Environment

Star Type
M-type (Red Dwarf)
Distance from Star
2.47 AU (370 million km)
Orbital Period
7.09 years

Atmosphere

Deep hydrogen-helium envelope with photochemical haze

Elemental Composition

O - Oxygen
31.3%
Si - Silicon
25.0%
Fe - Iron
12.5%

Surface Characteristics

No solid surface - a hydrogen-helium envelope wrapped around a rocky core (a sub-Neptune)
Love TerraForge? Please help support us.Keeps it ad-free, and funds new features and hosting.
The surface of TOI-700 d as TerraForge draws it: red-leaved trees over green ground under a lavender sky

New: Stand on a Planet in VR 🥽

Open any planet's surface view on your phone and look around just by moving it: hold it up, turn on the spot, and the view turns with you. In Chrome on Android you also get a VR button, in the row along the bottom:

The surface view's bottom row of buttons on a phone, with an arrow pointing to the VR button beside full screen

Tap it, drop your phone into a headset viewer, and you're standing on the ground under a star that isn't ours. It only appears where your browser can do VR.

Create your free account

Enter your email and we'll send a 6-digit code — no password needed.
We only keep your email and the username you choose. We never share or sell your email, and we don't send marketing — we use it only to email you a sign-in code. Read our privacy policy.

Send feedback

We're still building out the best experience we can — and we'd love your input. Tell us about features you enjoy, ideas you'd like to see, or pain points where something feels off, and we'll know where to look next.

Type
Idea
Bug
Pain point
Other