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Entering orbit…
Habitability
0/ 100
Uninhabitable
MARVELS-17 b rendered in TerraForge from its measured mass, orbit and star

MARVELS-17 b

Also written MARVELS-17b, MARVELS 17b, MARVELS 17 b

Brown DwarfUninhabitable606 light years awayFound 2017
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

MARVELS-17 b, from the Extrasolar Planets Encyclopaedia (found 2017). Measured: 4160 Earth masses, 0.45 AU, a 6090 K F-type star. Composition inferred from a mass of 4160 Earths, which is giant territory whatever its 2.24x density suggests, with an assumed 24-hour day — rotation cannot be measured for exoplanets.

Host star

TYC 3547-1007-1

Type
F-type (White)
Spectral type
G1V
Temperature
6,090 K
Radius
0.91 ☉
Mass
1.12 ☉
Known planets
1 (this one)
Luminosity
1.03 ☉

Published by the Extrasolar Planets Encyclopaedia. This world’s temperature and habitability score are computed from its star’s published radius and temperature.

Brown Dwarf

Magnetic FieldNone Activity
Why is this a Brown Dwarf?
MARVELS-17 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: 4160.0x EarthTemperature: 418K

Reading MARVELS-17 b’s atmosphere

Dominant elements: H, He, O, C, NThis is what a telescope would measure while MARVELS-17 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.MARVELS-17 b sits about 607 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.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.
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Habitability ScoreUninhabitable
0
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 Field20
A strong field, but no surface beneath it — there is nothing here for it to shelter
geology30
Geologically dead - no nutrient recycling
Organic Chemistry80
Core organic elements (CHNO) present
rotation100
Optimal rotation period - balanced day/night cycle, moderate weather, and good heat distribution

Physical Properties

Mass
4160.00x Earth (2.48e+28 kg)
Radius
16.08x Earth (102,464 km)
This planet: 16.08× Earth radiusEarth: 1× (baseline)
Surface Gravity
16.08x Earth (157.8 m/s²)
Surface Temperature
418 K (145 °C / 294 °F)
Rotation Period
24.0 hours/day
This planet: 24 h/dayEarth: 24 h/day

Orbital Environment

Star Type
F-type (White)
Distance from Star
0.45 AU (67.3 million km)
Orbital Period
97 days

Atmosphere

Cold hydrogen and helium with ammonia and water clouds

Elemental Composition

H - Hydrogen
53.8%
He - Helium
32.3%
O - Oxygen
5.4%

Surface Characteristics

No surface: the coldest class of failed star, barely warmer than a summer day and glowing only in the infrared
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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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