HD 40307 d
HD 40307 d orbits the star HD 40307, 42.2 light-years from Earth. It completes an orbit in 20.432 Earth days.
Get to know this world ↓Size-based classification; composition may be uncertain.
Time to complete one orbit.
Its light travels for roughly 42 years to reach us.
Radial Velocity
Overview
HD 40307 d is one of the confirmed worlds in the NASA Exoplanet Archive. Recorded as discovered in 2009. 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 radius is not currently available in this catalogue, so we leave its size class unassigned.
The planet
The archive lists a mass or minimum-mass value of 1,775.39 Earth masses (Mass).
Mass and radius constrain possible interiors; multiple compositions can fit a given set of measurements.
Orbit & year
A year here lasts 20.432 Earth days. Its recorded semi-major axis is 0.132 AU. One AU is roughly the Earth–Sun distance.
Eccentricity: 0.07. Zero describes a circular orbit; increasing values describe more elongated ellipses.
Host star
Planetary system
5 confirmed planets are stored for this star.
HD 40307 b · 4.312-day orbit
HD 40307 c · 9.618-day orbit
HD 40307 d · 20.432-day orbit
HD 40307 f · 51.76-day orbit
HD 40307 g · 197.8-day orbit
Discovery
Reported discovery year: 2009. 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 541 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
| Mass / minimum mass | 1,775.38948 Earth masses (Mass) |
|---|---|
| Orbital period | 20.432 Earth days |
| Semi-major axis | 0.1321 AU |
| Eccentricity | 0.07 |
| Equilibrium temperature | 541 K · estimated, not surface temperature |
| Host star temperature | 4,956 K |
| Host star mass | 0.77 Solar masses |
| Host star radius | 0.71668 Solar radii |
| Distance | 12.9363 parsecs |
| Discovery year | 2,009 |
| Discovery method | Radial Velocity |
| Discovery facility | La Silla Observatory |
| Discovery publication | 2009-01 |
| Stellar spectral type | K2.5 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 |
|---|---|
| Mass / minimum mass | Upper uncertainty unavailable / Lower uncertainty unavailableSource limit flag: 1Kiefer et al. 2021 |
| Orbital period | +0.022 / -0.024 Tuomi et al. 2013 |
| Equilibrium temperature | +625 / -625Brasser et al. 2014 |
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.