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Gas Giant

TOI-257 b

Orbiting TOI-257 | 76.9 parsecs away

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TOI-257 b is a Gas Giant exoplanet (a massive planet composed primarily of hydrogen and helium), about 7.2 times the radius of Earth. Its scorching equilibrium temperature of 1027 K (754°C) makes it far too hot for liquid water. The planet completes one orbit around its star every 18.4 Earth days. It was discovered in 2021 using the transit method. It orbits the star TOI-257, located approximately 77 parsecs (251 light-years) from Earth.

2021

Discovered

43.9

Earth Masses

7.16

Earth Radii

1027

Temperature (K)

Discovery Information

Discovery MethodTransit
Discovery Year2,021
Discovery FacilityTransiting Exoplanet Survey Satellite (TESS)

Orbital Properties

Orbital Period18.3882 days
Semi-Major Axis0.1528 AU
Eccentricity0
Inclination87.91 deg

Physical Properties

Mass (Jupiter)0.138 MJ
Mass (Earth)43.8603 M⊕
Radius (Jupiter)0.639 RJ
Radius (Earth)7.1625 R⊕
Density0.65 g/cm3
Eq. Temperature1,027 K
Insolation Flux186 S⊕
Planetary Extremes

Where TOI-257 b sits on the spectrum of all known exoplanets.

Mass43.9 M⊕
FeatherweightColossus
Radius7.16 R⊕
TinyEnormous
Temperature1027 K
FrozenInferno
Year Length18.4 days
LightningGlacial
Density0.65 g/cm³
FluffyIron-dense
Star Distance0.153 AU
ScorchedFrozen exile
Star System View
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Size Comparison
EarthTOI-257 bJupiter

7.16x Earth's radius (0.64x Jupiter)

Orbit Comparison
EarthTOI-257 b
Earth: 365.25 days (1 AU)TOI-257 b: 18.4 Earth days (0.153 AU)
Host Star: TOI-257

Effective Temperature6,095 K
Mass1.407 M☉
Radius1.867 R☉
Size vs Sun1.87x larger
Luminosity4.33 L☉
Luminosity vs Sun4.330x brighter
Metallicity [Fe/H]0.175
Distance (pc)76.9028 pc
Distance (ly)250.8 light-years
Planets in the TOI-257 System

What If You Lived Here?

59.8 kg

Your weight (from 70 kg)

0.85g

Earth-like

Feels just like home — comfortably familiar.

18.4 Earth days

Year length

Unknown sunrise

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