Space Codex / Exoplanet reference
Published exoplanet measurements
HD 21749 c
HD 21749 c orbits GJ 143 once every 7.78993 days. The system is about 53.2287 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 7.78993 days, or 0.0213277 Earth years. Its reported semimajor axis is 0.0695 AU. That orbital scale is 0.179541 times Mercury's semimajor axis. 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
The radius parameter is 0.892 (+0.064 / −0.058) Earth radii. Radius describes size; it does not specify the mass or the atmospheric composition. The mass parameter is Upper limit: 3.7 Earth masses. Its archive provenance is Mass. The source lists a bulk-density parameter of Upper limit: 31.93 g/cm³. Different interior mixtures can overlap in density; the value does not identify a unique surface.
The host star and received light
The host is cataloged as GJ 143. The selected row gives spectral type K4.5. Its reported effective temperature is 4640 K. Its reported radius is 0.695 solar radii. Its reported mass is 0.73 solar masses. The equilibrium-temperature entry is 701 (+25 / −23) K. This is a model quantity, not a measured surface temperature. 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 143
The fetched archive contains 2 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 |
|---|---|---|---|---|
| HD 21749 c | 7.78993 (+0.00051 / −0.00044) | 0.892 (+0.064 / −0.058) | Upper limit: 3.7 | Mass |
| GJ 143 b | 35.6125 (+0.0006 / −0.00062) | 2.61 (+0.17 / −0.16) | 22.7 (+2.2 / −1.9) | Mass |
Earth comparison
| Quantity | Reported value or conversion | Comparison |
|---|---|---|
| Orbital period | 7.78993 days | 0.0213277 Earth years |
| System distance | 16.32 parsecs | 53.2287 light-years |
| Orbital scale | 0.0695 (+0.0021 / −0.0023) | AU; Earth = 1 |
| Radius | 0.892 (+0.064 / −0.058) | Earth radii; Earth = 1 |
| Mass parameter | Upper limit: 3.7 | Earth masses; check mass definition |
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 | 7.78993 (+0.00051 / −0.00044) | days |
| Semimajor axis | 0.0695 (+0.0021 / −0.0023) | AU |
| Radius | 0.892 (+0.064 / −0.058) | Earth radii |
| Mass parameter | Upper limit: 3.7 | Earth masses |
| Orbital eccentricity | Not reported in this solution | dimensionless |
| Orbital inclination | 88.9 (+0.5 / −0.37) | degrees |
| Equilibrium temperature | 701 (+25 / −23) | K; model estimate |
| Incident flux | Not reported in this solution | Earth flux |
| Bulk density | Upper limit: 31.93 | g/cm³ |
| Host effective temperature | 4640 (+100 / −100) | K |
| Host radius | 0.695 (+0.03 / −0.03) | solar radii |
| Host mass | 0.73 (+0.07 / −0.07) | solar masses |
| Host metallicity | 0.003 (+0.06 / −0.06) | dex; archive abundance definition |
| Host age | 3.8 (+3.7 / −3.7) | billion years |
| Host luminosity | -0.6862 (+0.00034 / −0.00034) | log10 solar luminosity |
| Host surface gravity | 4.613 (+0.052 / −0.061) | log10 cm/s² |
| Host rotation period | Not reported in this solution | days |
| System distance | 16.32 (+0.0071 / −0.0071) | 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 | Dragomir et al. 2019 |
| Discovery method | Transit |
| Discovery year | 2019 |
| Discovery facility | Transiting Exoplanet Survey Satellite (TESS) |
| Mass provenance | Mass |
| Host stars in system | 1 |
| Archive system planet count | 2 |
| Planetary solution publication date | 2019-04 |
| Row update date | 2019-04-22 |
| Archive release date | 2019-04-25 |
Source: NASA Exoplanet Archive overview for HD 21749 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.