Finding Earth 2.0
HD 209458 · G0 V

HD 209458 b

Rank #5237 of the ranked catalogue · Discovered by Radial Velocity in 1999

HZ 0%measured

0.063

Earth-2.0 index

0.078

Earth Similarity Index

0%

Habitable-zone probability

15.58 R⊕

Radius

Planet

Mass232.016 M⊕measured
Bulk density0.362 g/cm³
Orbital period3.5248 days
Semi-major axis0.04707 au
Eccentricity0.000
Incident flux587.098 S⊕
Equilibrium temperature1251.2 K
Transit-time σ at 20301.7 minLinear propagation of published epoch and period errors; not a ranking input.
Maximum angular separation0.97 masReflected-light contrast 1.90e-5 at Aᵍ = 0.30 and Lambertian quadrature.
Composite parameter sources7 · mixedThe archive may select different publications for different parameters; mixed-source is disclosed, not automatically penalised.
Default-solution coverage67%0% median composite-to-default difference over shared parameters.

Host star & system

HostHD 209458
Spectral typeG0 V
Effective temperature6091 K
Radius1.190 R☉
Mass1.230 M☉
Distance48.3 pc / 157.5 ly
DiscoveryRadial Velocity, 1999