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Entering orbit…
Habitability
16/ 100
Uninhabitable
HD 102365 Ab rendered in TerraForge from its measured mass, orbit and star

HD 102365 Ab

Ice GiantUninhabitable30 light years awayFound 2011
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

HD 102365 Ab, from the Extrasolar Planets Encyclopaedia (found 2011). Measured: 15.9 Earth masses, 0.46 AU, a 5650 K G-type star. Composition inferred from a estimated bulk density of 0.23x Earth's, modeled rather than measured since this isn't a transiting planet, larger than even a pure water/ice world of this mass, suggesting a water-rich interior under roughly a 16% hydrogen/helium envelope by mass, with an assumed 24-hour day — rotation cannot be measured for exoplanets.

Host star

HD 102365 A

Type
G-type (Yellow (Sun-like))
Spectral type
G2V
Temperature
5,650 K
Mass
0.85 ☉
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 G-type star.

Ice Giant

Magnetic FieldExtreme Activity
Why is this a Ice Giant?
HD 102365 Ab has moderate mass (15.9x Earth) with significant water, carbon, and nitrogen content, characteristic of ice giants.
Ice giants like Uranus and Neptune have icy interiors with thick atmospheres of hydrogen and helium, but not enough to be classified as gas giants.
Classification Criteria:
✓ Mass: 15.9x Earth (5-20x range)✓ Water/Carbon/Nitrogen rich composition

Reading HD 102365 Ab’s atmosphere

Dominant elements: H, O, Si, He, Fe, NThis is what a telescope would measure while HD 102365 Ab 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.HD 102365 Ab sits about 30 light-years away, found by the radial velocity 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.
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Habitability ScoreUninhabitable
16
Contributing Factors
temperature15
Extremely hot - hostile to known life forms
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
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
15.90x Earth (9.50e+25 kg)
Radius
2.51x Earth (16,020 km)
This planet: 2.51× Earth radiusEarth: 1× (baseline)
Surface Gravity
2.51x Earth (24.7 m/s²)
Surface Temperature
427 K (154 °C / 309 °F)
Rotation Period
24.0 hours/day
This planet: 24 h/dayEarth: 24 h/day

Orbital Environment

Star Type
G-type (Yellow (Sun-like))
Distance from Star
0.46 AU (68.8 million km)
Orbital Period
114 days

Atmosphere

Hydrogen and helium with water, methane, and ammonia ices

Elemental Composition

H - Hydrogen
54.8%
O - Oxygen
26.3%
Si - Silicon
5.1%

Surface Characteristics

No solid surface - a deep volatile envelope over a supercritical water mantle and hot-ice interior
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The surface of TOI-700 d as TerraForge draws it: red-leaved trees over green ground under a lavender sky

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

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