Temperature
4664.8 K
4471.4 to 4695
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Stellar HostProfile
K2-121
Unclassified star • 169.4 pc
Records
12
literature rows
Planets
1
system count
References
13
distinct source labels
TIC: TIC 7059054
Approximate color
from effective temperature
Canonical Summary
Adopted host values from one source row
Values come from the row with the most populated summary measurements. Missing values stay missing. Ranges and counts describe all source rows.
Stellar source: TICv8 • System source: TICv8
Mass
0.74 Msun
0.69 to 0.74
Radius
0.65 Rsun
0.64 to 0.77
Luminosity
-0.75 log(Lsun)
-0.76 to -0.75
Distance
169.4 pc
single adopted value
Planets
1
Stable across source rows
Scale Comparison
Radius against the Sun
Current adopted radius: 0.65 R☉ (circles scaled linearly by radius)
Sun
1.0 R☉ baseline
K2-121
0.65 R☉
System Layout
Known planets
1 planets linked to this host
K2-121 b
Transit
◌
Discovery
2017
Period
5.19 days
Radius
7.16 R⊕
Mass
51 M⊕
Eq. Temp
716 K
K2-121 b: A Distant Jupiter-like World
K2-121 is a star 553 light-years away with one known planet. The host star has a mass of 0.74 solar masses and a radius of 0.649 solar radii, and its temperature is 4660 K. Each of these estimates is smaller or cooler than the corresponding value for the Sun.
The sole known planet, K2-121 b, is a Jupiter-like world, a size class that describes radii exceeding 4 times Earth's radius. It was discovered in 2017 by the transit method, in which a planet passing in front of its star from our viewpoint causes a small dip in observed brightness. Repeated dips help establish orbital periods. K2-121 b completes an orbit every 5.19 days.
K2-121 b has a radius of 7.16 Earth radii and a mass of 51 Earth masses, both larger than Earth's corresponding values. Its mean density is 0.766 g/cm³, 0.139 times Earth's.
Provenance
Underlying measurements and references
Evidence Summary
Rows
12
Stellar refs
12
System refs
1
Distancestable
Parallaxstable
Temperaturedisputed
Massdisputed
Radiusdisputed
Luminositydisputed
Surface Gravitydisputed
Metallicitydisputed
| ST TEFF | ST MASS | ST RAD | ST AGE | ST LUM | ST SPECTYPE | SY DIST | Stellar Ref | System Ref |
|---|---|---|---|---|---|---|---|---|
| 4695 | 0.73 | 0.69 | — | — | — | 169.4 | Mayo et al. 2018 | TICv8 |
| — | — | — | — | — | — | 169.4 | Pope et al. 2016 | TICv8 |
| 4680.4 | — | 0.64 | — | -0.76 | — | 169.4 | Gaia DR2 | TICv8 |
| 4526 | 0.71 | 0.68 | — | — | — | 169.4 | Howard et al. 2025 | TICv8 |
| 4690 | 0.69 | 0.67 | — | — | — | 169.4 | Castro-González et al. 2022 | TICv8 |
| — | — | 0.71 | — | — | — | 169.4 | Petigura et al. 2018 | TICv8 |
| 4551 | 0.72 | 0.68 | — | — | — | 169.4 | Livingston et al. 2018 | TICv8 |
| 4664.8 | 0.74 | 0.65 | — | -0.75 | — | 169.4 | TICv8 | TICv8 |
| — | — | — | — | — | — | 169.4 | Barros et al. 2016 | TICv8 |
| — | — | 0.64 | — | — | — | 169.4 | Kruse et al. 2019 | TICv8 |
| 4471.4 | 0.71 | 0.77 | — | — | — | 169.4 | Dressing et al. 2017 | TICv8 |
| 4664.8 | — | 0.65 | — | — | — | 169.4 | ExoFOP | TICv8 |