HN Peg b
HN Peg b orbits the star HN Peg, 59.1 light-years from Earth.
Get to know this world ↓Size-based classification; composition may be uncertain.
Around 1,078% wider than Earth.
Its light travels for roughly 59 years to reach us.
Imaging
Overview
HN Peg b is one of the confirmed worlds in the NASA Exoplanet Archive. Recorded as discovered in 2006. The credited discovery facility is Spitzer Space Telescope. Its Imaging evidence gives us a way to study a planet that is usually too faint to see directly.
Its recorded radius is 11.78 times Earth's radius. Size is useful for comparison, but it cannot establish surface conditions by itself.
The planet
The archive lists a mass or minimum-mass value of 6,991.57 Earth masses (Mass). Radius: 11.78 Earth radii.
Mass and radius constrain possible interiors; multiple compositions can fit a given set of measurements.
Orbit & year
The orbital period is not determined in this record. Its recorded semi-major axis is 773 AU. One AU is roughly the Earth–Sun distance.
Host star
Planetary system
1 confirmed planets are stored for this star.
HN Peg b · Orbit not determined
Discovery
Reported discovery year: 2006. Method: Imaging. Facility: Spitzer Space Telescope.
First stored in this atlas: 04/10/2026. This is an ingestion date, not a confirmation date.
How these methods work ↗Potential habitability
The data here does not establish habitability, liquid water, or life. An appropriate atmosphere and many other conditions would be needed.
The listed equilibrium temperature is 11 K. This is an estimated energy-balance temperature, not a measured surface temperature.
Understand the habitable zone ↗What do we actually know?
The underlying light, motion or timing signal. Usually not a photograph of the planet.
Parameters derived from observations, with instrument and model uncertainty.
Our light-year conversion and browsing class are calculated from archive values.
Equilibrium temperature is an energy-balance estimate, not surface weather.
Possible composition depends on models and may not be unique.
Surface conditions and the presence of life are not established here.
Measured signals are interpreted through models. The archive’s composite table combines published values and may include calculated estimates. Values do not necessarily form one self-consistent solution.
Radius and mass can be estimated or inferred, orbital period comes from recurring observations, and size classification is calculated by this site. Atmospheric and surface conditions remain unknown unless established by specific observations.
Consult the archive for individual parameter references and uncertainty intervals before scientific use.
Scientific data
| Radius | 11.7768 Earth radii |
|---|---|
| Mass / minimum mass | 6,991.57 Earth masses (Mass) |
| Semi-major axis | 773 AU |
| Equilibrium temperature | 10.77 K · estimated, not surface temperature |
| Host star temperature | 6,186 K |
| Host star mass | 1.08 Solar masses |
| Host star radius | 1.00695 Solar radii |
| Distance | 18.1186 parsecs |
| Discovery year | 2,006 |
| Discovery method | Imaging |
| Discovery facility | Spitzer Space Telescope |
| Discovery publication | 2007-01 |
| Stellar spectral type | G0 V |
Uncertainties and parameter provenance
Archive uncertainty ranges and published references, where available. A missing uncertainty does not imply an exact value.
| Parameter | Uncertainty / source |
|---|---|
| Radius | +1.52663 / -0.65427 Luhman et al. 2007 |
| Mass / minimum mass | +2,996.39 / -2,996.39 Luhman et al. 2007 |
| Equilibrium temperature | +0.18 / -0.18Calculated Value |
Sources
NASA Exoplanet Archive · Planetary Systems Composite Parameters (PSCompPars).
Open the scientific archive record ↗Last changed in this atlas: 05/10/2026, 05:04:57. Read our methodology.