Space Codex / Exoplanet reference
Published exoplanet measurements
HD 101581 c
HD 101581 c orbits HIP 56998 once every 6.20401 days. The system is about 41.6766 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 6.20401 days, or 0.0169857 Earth years. Its reported semimajor axis is 0.0573 AU. That orbital scale is 0.148025 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 0.99 (+0.07 / −0.07) Earth radii. Radius describes size; it does not specify the mass or the atmospheric composition. No mass parameter is supplied in this solution, so this record cannot establish bulk composition from size and mass together.
The host star and received light
The host is cataloged as HIP 56998. Its reported effective temperature is 4675 K. Its reported radius is 0.63 solar radii. Its reported mass is 0.653 solar masses. The planet's incident-flux parameter is 52 (+6 / −5) times Earth's received stellar flux. The equilibrium-temperature entry is 747 (+21 / −20) 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 HIP 56998
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 101581 b | 4.46569 (+0.00029 / −0.00032) | 0.956 (+0.061 / −0.063) | Not reported in this solution | Not specified |
| HD 101581 c | 6.20401 (+0.00054 / −0.00044) | 0.99 (+0.07 / −0.07) | Not reported in this solution | Not specified |
Earth comparison
| Quantity | Reported value or conversion | Comparison |
|---|---|---|
| Orbital period | 6.20401 days | 0.0169857 Earth years |
| System distance | 12.7781 parsecs | 41.6766 light-years |
| Orbital scale | 0.0573 (+0.0009 / −0.0009) | AU; Earth = 1 |
| Radius | 0.99 (+0.07 / −0.07) | Earth radii; Earth = 1 |
| Received stellar flux | 52 (+6 / −5) | 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 | 6.20401 (+0.00054 / −0.00044) | days |
| Semimajor axis | 0.0573 (+0.0009 / −0.0009) | AU |
| Radius | 0.99 (+0.07 / −0.07) | Earth radii |
| Mass parameter | Not reported in this solution | Earth masses |
| Orbital eccentricity | Not reported in this solution | dimensionless |
| Orbital inclination | 87.93 (+0.19 / −0.15) | degrees |
| Equilibrium temperature | 747 (+21 / −20) | K; model estimate |
| Incident flux | 52 (+6 / −5) | Earth flux |
| Bulk density | Not reported in this solution | g/cm³ |
| Host effective temperature | 4675 (+53 / −53) | K |
| Host radius | 0.63 (+0.027 / −0.027) | solar radii |
| Host mass | 0.653 (+0.028 / −0.028) | solar masses |
| Host metallicity | -0.343 (+0.059 / −0.059) | dex; archive abundance definition |
| Host age | 6.88 (+4.27 / −4.27) | billion years |
| Host luminosity | Not reported in this solution | log10 solar luminosity |
| Host surface gravity | 4.654 (+0.057 / −0.057) | log10 cm/s² |
| Host rotation period | Not reported in this solution | days |
| System distance | 12.7781 (+0.0114 / −0.0114) | 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 | Kunimoto et al. 2025 |
| Discovery method | Transit |
| Discovery year | 2025 |
| Discovery facility | Transiting Exoplanet Survey Satellite (TESS) |
| Mass provenance | Not specified |
| Host stars in system | 1 |
| Archive system planet count | 2 |
| Planetary solution publication date | 2025-01 |
| Row update date | 2025-01-22 |
| Archive release date | 2025-01-22 |
Source: NASA Exoplanet Archive overview for HD 101581 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.