Gas giant · HN Peg

HN Peg b

ExoplanetsDiscovered 2006

Scientific overview

HN Peg b is a gas giant orbiting HN Peg, about 59 light-years from Earth. It was discovered in 2006 using the direct imaging.

Host star

Spectral type

G0 V

Temperature

6,186 K

Mass

1.08 M☉

Discovery and detection

Detection method

Discovery year

2006

Spitzer Space Telescope

Knowledge connections

OrbitsHN Peg
Discovered by methodDirect Imaging
Discovered by missionSpitzer Space Telescope
Catalogued inNASA Exoplanet Archive

Quick facts

Class: Gas giant
Host star: HN Peg
Discovery method: Direct Imaging
Discovery year: 2006
Semi-major axis: 773 AU
Radius: 11.78 R⊕
Mass: 6991.57 M⊕
Density: 23.58 g/cm³ · derived
Equilibrium temp.: 11 K
Distance: 59 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 density23.58 g/cm³derived
Formula & inputs
Formula: ρ = M / (4⁄3·π·r³) (v1.0.0, impl v1.0.0)
Inputs:
- massEarth = 6991.57 M⊕ · NASA
- radiusEarth = 11.78 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.