Discovery Method
Transit
Consistent across records
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ExoplanetDetail
K2-138 d
Host star K2-138 • 2.39 R⊕ • 5.40 d orbit
Records
4
archive rows
Discovery
2017
Transit
Radius
2.39 R⊕
default parameter set
Mass
7.92 M⊕
default parameter set
K2-138
temperature unconstrained
Canonical Summary
Adopted planet values from the default parameter set
Values come from the archive's default parameter set. Missing values stay missing. Ranges and counts describe all source rows.
Selected source: Lopez et al. 2019
Host Star
K2-138
Stable across source rows
Discovery Year
2017
Stable across source rows
Orbital Period
5.40 day
5.40 to 5.41
Semi-Major Axis
0.06 au
0.06 to 0.06
Radius
2.39 Rearth
2.39 to 2.66
Mass
7.92 Mearth
0.78 to 7.92
Density
3.10 g/cm**3
single adopted value
Scale Comparison
Radius against familiar reference worlds
Current adopted radius: 2.39 R⊕ • circles scaled linearly by radius
Earth
1.0 R⊕ baseline
K2-138 d
2.39 R⊕
Jupiter
11.2 R⊕ reference
Provenance
Underlying measurements and references
Evidence Summary
Rows
4
Refs
4
Methods
1
Discoverystable
Facilitystable
Perioddisputed
Radiusdisputed
Massdisputed
Eq. Tempstable
| Year | Method | Facility | Telescope | Period | Radius | Mass | Eq. Temp | Reference |
|---|---|---|---|---|---|---|---|---|
| 2017 | Transit | K2 | 0.95 m Kepler Telescope | 5.41 day | — | 0.78 Mearth | — | Vivien et al. 2024 |
| 2017 | Transit | K2 | 0.95 m Kepler Telescope | 5.40 day | 2.66 Rearth | — | — | Christiansen et al. 2018 |
| 2017 | Transit | K2 | 0.95 m Kepler Telescope | 5.40 day | 2.46 Rearth | — | 888 K | Hardegree-Ullman et al. 2021 |
| 2017 | Transit | K2 | 0.95 m Kepler Telescope | 5.40 day | 2.39 Rearth | 7.92 Mearth | — | Lopez et al. 2019 |