Key parameters at a glance
- A radius of 1.01 Earth radii
- A mass of 4.30 Earth masses
- Surface gravity around 4.18 g
- An orbital period of 7.975 days
- Semi-major axis 0.0707 AU
- Equilibrium temperature 610 K (337 °C)
- Distance from Earth 193.24 light-years
- Earth Similarity Index 0.384
- Travel time at Voyager 1 speed 3,407,769 years
- Almost certainly tidally locked to its host star given the close orbit
2 siblings around K2-136
K2-136 b shares its host star with 2 other confirmed planets. Side-by-side measurements below.
K2-136 b Planet Profile
Physical Specs
Classification
Planet Type
Rocky Terrestrial
Discovery
Size rank in cohort
Rank by radius
#323of 570
top 56.5%
This planet
1.01R⊕
Rocky Terrestrial median
1.01R⊕
Nearest-size peers
| Metric | Earth | K2-136 b | Jupiter |
|---|---|---|---|
| Radius (R⊕) | 1.00 | 1.01 | 11.21 |
| Mass (M⊕) | 1.00 | 4.30 | 317.83 |
| Density (g/cm³) | 5.51 | 24.00 | 1.33 |
| Surface Gravity (g) | 1.00 | 4.18 | 2.53 |
| Insolation (S⊕) | 1.00 | 33.50 | 0.037 |
Alternative Mass Estimates
| Method | Value | Interpretation |
|---|---|---|
| Best measured mass | 4.300 M⊕ | Direct mass measurement (not derived). |
Star Catalogue Identifiers
TIC
TIC 18310799
Gaia DR2
Gaia DR2 145916050683920128
Gaia DR3
Gaia DR3 145916050683920128
System
K2-136
Percentile among Rocky Terrestrial cohort
Orbit & Habitability
Orbital Dynamics
Year Length
A year here lasts approximately 7.98 Earth days (2.2% of a terrestrial year) on a mildly elliptical path at a mean orbital distance of 0.0707 AU.
Transit Fingerprint
Duration
2.670 h
Impact parameter b
0.220
Rp / R★
0.013700
Transit midpoint (BJD)
2,457,817.7563
Extended Orbital Architecture
Planet / star radius ratio
0.013700
Semi-major axis / stellar radius
22.200
Impact parameter (b)
0.220
RV semi-amplitude (K)
1.700 m/s
Transit mid-time (BJD)
2,457,817.7563
Long. of periastron (ω)
189.00°
Angular separation (arcsec)
1.19000
Eq. Temperature
610K
(337 °C)
Insolation (S⊕)
33.50
Earth = 1.00
Earth Similarity (ESI)
0.384
0 = alien, 1 = Earth-identical
Inside the inner HZ boundary (too hot for liquid water) — the surface is too hot to retain surface water. Close-orbiting tidally-locked around a cool host.
Discovery Paper
Primary reference
Mann et al. 2018Instrument
Kepler CCD Array
Publication
2018-01
Observation locale
Space
Discovery cohort
Planets confirmed in 2017 at K2 (12 shown).
Host System: K2-136
Spectral Class
K-type orange
Effective Temperature
4,500 K — cooler than the Sun (5,778 K)
Estimated Age
0.65 Gyr — younger than the Sun (4.6 Gyr)
Stellar Radius
0.677 R☉
Stellar Mass
0.742 M☉
Metallicity [Fe/H]
-0.02
Extended Stellar Properties
Surface gravity (log g)
4.680 dex
Stellar density
3.384 g/cm³
Systemic radial velocity
39.20 km/s
Rotational v·sin i
2.00 km/s
Rotation period
15.00 days
Metallicity ratio
[M/H]
Multi-band Host Photometry — 17 bands
Astrometric Data
Parallax
16.850 mas
Total Proper Motion
90.204 mas/yr
PM Right Ascension
82.87 mas/yr
PM Declination
-35.62 mas/yr
Galactic Cartesian (pc)
x = 0.354 · y = 0.851 · z = 0.389
Equatorial (J2000)
RA 67.41286° · Dec 22.88257°
Galactic ℓ, b
174.775° · -17.351°
Ecliptic λ, β
69.269° · 1.054°
HTM-20 index
-1285742176
Similar Worlds
Kepler-398 c
Rocky Terrestrial · K-type orange
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Kepler-595 c
Rocky Terrestrial · K-type orange
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Kepler-1150 b
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Radius 1.02 R⊕ · 1,169.3 ly
EPIC 201833600 c
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Radius 1.00 R⊕ · 839.7 ly
EPIC 201754305 d
Rocky Terrestrial · K-type orange
Radius 1.03 R⊕ · 1,092.5 ly
K2-338 b
Rocky Terrestrial · K-type orange
Radius 1.03 R⊕ · 511.9 ly