Hot Jupiter · WASP-121

WASP-121 b

ExoplanetsDiscovered 2016

Scientific overview

WASP-121 b is a hot jupiter orbiting WASP-121, completing an orbit every 1.2749 days, about 880 light-years from Earth. It was discovered in 2016 using the transit method.

Host star

WASP-121

Spectral type

F6 V

Temperature

6,628 K

Mass

1.33 M☉

Discovery and detection

Detection method

Transit Method

Discovery year

2016

Knowledge connections

OrbitsWASP-121
Discovered by methodTransit Method
Catalogued inNASA Exoplanet Archive

Quick facts

Class: Hot Jupiter
Host star: WASP-121
Discovery method: Transit Method
Discovery year: 2016
Orbital period: 1.2749 d
Semi-major axis: 0.0257 AU
Eccentricity: 0
Radius: 19.53 R⊕
Mass: 371.86 M⊕
Density: 0.28 g/cm³ · derived
Equilibrium temp.: 2409 K
Insolation: 6216.41 S⊕
Distance: 880 ly

Density is derived from the archive mass and radius via ρ = M / (4⁄3·π·r³); all other values are catalogued measurements.

Derived values

Computed from source-backed inputs via standard formulae — not observations. Every input and constant is traced below.

Bulk density0.28 g/cm³derived
Formula & inputs
Formula: ρ = M / (4⁄3·π·r³) (v1.0.0, impl v1.0.0)
Inputs:
- massEarth = 371.86 M⊕ · NASA
- radiusEarth = 19.53 R⊕ · NASA
Assumptions: M⊕ = 5.972e+24 kg, R⊕ = 6371000 m (IAU 2015 B3 nominal); Assumes a uniform sphere.
Limitations: Withheld above 30 g/cm³ (inconsistent mass/radius inputs).; Archive mass/radius carry no propagated uncertainty here.
Uncertainty: not propagated (inputs carry no catalogued uncertainty)
Computed as of 2026-06-29.

Quality & authority

Partial

Unreviewed

Description: Complete
Source coverage: Partial
Relationship coverage: Complete
Review coverage: None
Citation coverage: None
Image coverage: Not applicable

Data from the NASA Exoplanet Archive. See source quality.