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CONFIRMED EXOPLANET · Neptune-like

HD 20003 b

HD 20003 b orbits the star HD 20003, 136.4 light-years from Earth. It completes an orbit in 11.848 Earth days.

DISCOVERED 2019 · Radial Velocity

Get to know this world ↓
HD 20003 b
ORBITAL VISUALISATION
Neptune-likePlanet type

Size-based classification; composition may be uncertain.

3.43 × Earth’s radiusSize

Around 243% wider than Earth.

11.848 daysYear length

Time to complete one orbit.

136.4 light-yearsDistance

Its light travels for roughly 136 years to reach us.

2019Discovered

Radial Velocity

Overview

HD 20003 b is one of the confirmed worlds in the NASA Exoplanet Archive. Recorded as discovered in 2019. The credited discovery facility is La Silla Observatory. Its Radial Velocity evidence gives us a way to study a planet that is usually too faint to see directly.

Its recorded radius is 3.43 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 11.66 Earth masses (Msini). Radius: 3.43 Earth radii.

Mass and radius constrain possible interiors; multiple compositions can fit a given set of measurements.

Orbit & year

A year here lasts 11.848 Earth days. Its recorded semi-major axis is 0.097 AU. One AU is roughly the Earth–Sun distance.

Eccentricity: 0.36. Zero describes a circular orbit; increasing values describe more elongated ellipses.

Host star

HD 20003 · G8 V.

Effective temperature: 5,494 K.

Mass: 0.88 times the Sun’s mass.

Planetary system

2 confirmed planets are stored for this star.

HD 20003 b · 11.848-day orbit

HD 20003 c · 33.924-day orbit

Discovery

Reported discovery year: 2019. Method: Radial Velocity. Facility: La Silla Observatory.

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 815 K. This is an estimated energy-balance temperature, not a measured surface temperature.

Understand the habitable zone ↗

What do we actually know?

Observed

The underlying light, motion or timing signal. Usually not a photograph of the planet.

Measured

Parameters derived from observations, with instrument and model uncertainty.

Calculated

Our light-year conversion and browsing class are calculated from archive values.

Estimated

Equilibrium temperature is an energy-balance estimate, not surface weather.

Inferred

Possible composition depends on models and may not be unique.

Unknown

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

Radius3.43 Earth radii
Mass / minimum mass11.66 Earth masses (Msini)
Orbital period11.8482 Earth days
Semi-major axis0.0974 AU
Eccentricity0.36
Equilibrium temperature814.93 K · estimated, not surface temperature
Host star temperature5,494 K
Host star mass0.875 Solar masses
Host star radius0.92164 Solar radii
Distance41.8316 parsecs
Discovery year2,019
Discovery methodRadial Velocity
Discovery facilityLa Silla Observatory
Discovery publication2019-02
Stellar spectral typeG8 V

Uncertainties and parameter provenance

Archive uncertainty ranges and published references, where available. A missing uncertainty does not imply an exact value.

ParameterUncertainty / source
RadiusUpper uncertainty unavailable / Lower uncertainty unavailableCalculated Value
Mass / minimum mass+1.04 / -1.06Udry et al. 2019
Orbital period+0.0016 / -0.0017Udry et al. 2019
Equilibrium temperature+21.14 / -21.14Calculated Value

Sources

NASA Exoplanet Archive · Planetary Systems Composite Parameters (PSCompPars).

Open the scientific archive record ↗

Last changed in this atlas: 04/10/2026, 11:39:41. Read our methodology.

Spotted something wrong? Report an error ↗

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