Space Codex / Exoplanet reference
Published exoplanet measurements
GJ 3998 c
GJ 3998 c orbits GJ 3998 once every 13.727 days. The system is about 59.184 light-years from Earth.
Archive retrieved November 1, 2026 (America/New_York). The selected paper and archive update dates appear below.
The recorded orbit
The selected archive solution gives an orbital period of 13.727 days, or 0.0375825 Earth years. Its reported semimajor axis is 0.09 AU. That orbital scale is 0.232499 times Mercury's semimajor axis. The listed eccentricity is 0. A zero may be a circular assumption fixed in the fit; consult the paper before treating it as an exact observed shape. The period measures a year on this planet. It does not establish the length of its rotation or the duration of daylight.
Read how orbital period, size, and eccentricity fit together.
Size and mass
No planetary radius is supplied in this selected solution. The profile leaves that gap visible rather than estimating a size from the mass. The mass parameter is 6.82 (+0.78 / −0.75) Earth masses. Its archive provenance is Msini. Read this provenance before comparing it with a true mass: an inclination-dependent minimum or another mass definition must keep its qualification.
The host star and received light
The host is cataloged as GJ 3998. Its reported effective temperature is 3726 K. Its reported radius is 0.5 solar radii. Its reported mass is 0.52 solar masses. The planet's incident-flux parameter is 5.4 (+1.3 / −1) times Earth's received stellar flux. The available stellar and orbital entries do not establish a breathable atmosphere, surface water, or life.
What a habitable-zone claim does and does not mean · How a star changes over time.
Other planets around GJ 3998
The fetched archive contains 3 selected default planet records for this host. This is the retrieved record set, and additional or revised discoveries may appear in later research.
| Planet | Period (days) | Radius (Earth) | Mass parameter (Earth) | Mass definition |
|---|---|---|---|---|
| GJ 3998 b | 2.65033 (+0.00022 / −0.00019) | Not reported in this solution | 2.5 (+0.3 / −0.29) | Msini |
| GJ 3998 c | 13.727 (+0.003 / −0.004) | Not reported in this solution | 6.82 (+0.78 / −0.75) | Msini |
| GJ 3998 d | 41.78 (+0.05 / −0.05) | Not reported in this solution | 6.07 (+1 / −0.96) | Msini |
Earth comparison
| Quantity | Reported value or conversion | Comparison |
|---|---|---|
| Orbital period | 13.727 days | 0.0375825 Earth years |
| System distance | 18.1459 parsecs | 59.184 light-years |
| Orbital scale | 0.09 (+0.003 / −0.003) | AU; Earth = 1 |
| Mass parameter | 6.82 (+0.78 / −0.75) | Earth masses; check mass definition |
| Received stellar flux | 5.4 (+1.3 / −1) | Earth flux; Earth = 1 |
Conversions use rounded central values. They are navigation aids for the data, not additional observations. Uncertainties for the original parameters remain in the next table.
Measurement table
| Parameter | Value and reported uncertainty | Unit or definition |
|---|---|---|
| Orbital period | 13.727 (+0.003 / −0.004) | days |
| Semimajor axis | 0.09 (+0.003 / −0.003) | AU |
| Radius | Not reported in this solution | Earth radii |
| Mass parameter | 6.82 (+0.78 / −0.75) | Earth masses |
| Orbital eccentricity | 0 | dimensionless |
| Orbital inclination | Not reported in this solution | degrees |
| Equilibrium temperature | Not reported in this solution | K; model estimate |
| Incident flux | 5.4 (+1.3 / −1) | Earth flux |
| Bulk density | Not reported in this solution | g/cm³ |
| Host effective temperature | 3726 (+68 / −68) | K |
| Host radius | 0.5 (+0.05 / −0.05) | solar radii |
| Host mass | 0.52 (+0.05 / −0.05) | solar masses |
| Host metallicity | -0.13 (+0.09 / −0.09) | dex; archive abundance definition |
| Host age | 8.38 (+4.06 / −4.06) | billion years |
| Host luminosity | -1.358 (+0.086 / −0.086) | log10 solar luminosity |
| Host surface gravity | 4.75 (+0.04 / −0.04) | log10 cm/s² |
| Host rotation period | Not reported in this solution | days |
| System distance | 18.1459 (+0.0165 / −0.0165) | parsecs |
Parentheses show the reported upper and lower uncertainties when both are supplied. Bounds are explicitly labeled. A missing entry means unavailable in this solution, not zero. The confidence convention belongs to the source paper.
Research record and limitations
| Record | Value |
|---|---|
| Planetary reference | Stefanov et al. 2025 |
| Discovery method | Radial Velocity |
| Discovery year | 2016 |
| Discovery facility | Roque de los Muchachos Observatory |
| Mass provenance | Msini |
| Host stars in system | 1 |
| Archive system planet count | 3 |
| Planetary solution publication date | 2025-03 |
| Row update date | 2025-03-11 |
| Archive release date | 2025-03-11 |
Source: NASA Exoplanet Archive overview for GJ 3998 c, Planetary Systems table, default solution. The collection excludes entries flagged controversial at retrieval. A selected default is a published reference choice, not a claim that every parameter is the latest estimate in all literature.
This profile documents measurements and their scope. It is separate from the 3D planet catalog and does not create a sponsorship placement or a new explorer destination.