Key parameters at a glance
- A radius of 14.57 Earth radii
- A mass of 273.33 Earth masses
- Surface gravity around 1.29 g
- An orbital period of 3.205 days
- Semi-major axis 0.0460 AU
- Equilibrium temperature 1,587 K (1314 °C)
- Distance from Earth 1,754.60 light-years
- Earth Similarity Index 0.077
- Travel time at Voyager 1 speed 30,942,345 years
K2-238 b Planet Profile
Physical Specs
Classification
Planet Type
Gas Giant
Discovery
Size rank in cohort
Rank by radius
#270of 1771
top 15.2%
This planet
14.57R⊕
Gas Giant median
13.52R⊕
Nearest-size peers
| Metric | Earth | K2-238 b | Jupiter |
|---|---|---|---|
| Radius (R⊕) | 1.00 | 14.57 | 11.21 |
| Mass (M⊕) | 1.00 | 273.33 | 317.83 |
| Density (g/cm³) | 5.51 | 0.56 | 1.33 |
| Surface Gravity (g) | 1.00 | 1.29 | 2.53 |
| Insolation (S⊕) | 1.00 | — | 0.037 |
Alternative Mass Estimates
| Method | Value | Interpretation |
|---|---|---|
| Best measured mass | 273.334 M⊕ | Direct mass measurement (not derived). |
Star Catalogue Identifiers
TIC
TIC 404243877
Gaia DR2
Gaia DR2 2631270757088861312
Gaia DR3
Gaia DR3 2631270761382148224
System
K2-238
Percentile among Gas Giant cohort
Orbit & Habitability
Orbital Dynamics
Year Length
A year here lasts approximately 3.20 Earth days (0.9% of a terrestrial year) on a nearly circular orbit at a mean orbital distance of 0.0460 AU.
Transit Fingerprint
Depth
0.745 %
Duration
3.331 h
Rp / R★
0.080000
Transit midpoint (BJD)
2,457,740.5036
Photometric dip
Transit produces a flux drop of 7,448 ppm lasting ≈ 3.33 h.
Extended Orbital Architecture
Planet / star radius ratio
0.080000
Semi-major axis / stellar radius
6.270
RV semi-amplitude (K)
100.000 m/s
Transit mid-time (BJD)
2,457,740.5036
Long. of periastron (ω)
90.00°
Angular separation (arcsec)
0.08550
Eq. Temperature
1,587K
(1314 °C)
Insolation (S⊕)
—
Earth = 1.00
Earth Similarity (ESI)
0.077
0 = alien, 1 = Earth-identical
Insufficient insolation data — the dayside is scorched.
Detection Signatures
Transit photometry
A transit dip has been observed from at least one telescope.
Radial velocity
Stellar wobble has been measured spectroscopically.
Discovery Paper
Primary reference
Soto et al. 2018Instrument
Kepler CCD Array
Publication
2018-08
Observation locale
Space
Discovery cohort
Planets confirmed in 2018 at K2 (12 shown).
Host System: K2-238
Spectral Class
G-type yellow (Sun-like)
Effective Temperature
5,630 K — cooler than the Sun (5,778 K)
Estimated Age
5.63 Gyr — older than the Sun (4.6 Gyr)
Stellar Radius
1.590 R☉
Stellar Mass
1.190 M☉
Metallicity [Fe/H]
0.34
Extended Stellar Properties
Surface gravity (log g)
4.110 dex
Stellar density
0.078 g/cm³
Rotational v·sin i
3.78 km/s
Metallicity ratio
[Fe/H]
Multi-band Host Photometry — 12 bands
Astrometric Data
Parallax
0.148 mas
Total Proper Motion
12.700 mas/yr
PM Right Ascension
-9.20 mas/yr
PM Declination
-8.70 mas/yr
Galactic Cartesian (pc)
x = 0.968 · y = -0.211 · z = -0.137
Equatorial (J2000)
RA 347.70432° · Dec -7.85756°
Galactic ℓ, b
67.227° · -59.357°
Ecliptic λ, β
345.628° · -2.379°
HTM-20 index
1761767988
Similar Worlds
WASP-35 b
Gas Giant · G-type yellow (Sun-like)
Radius 14.57 R⊕ · 659.5 ly
HATS-16 b
Gas Giant · G-type yellow (Sun-like)
Radius 14.57 R⊕ · 2,469.1 ly
WASP-135 b
Gas Giant · G-type yellow (Sun-like)
Radius 14.57 R⊕ · 972.6 ly
NGTS-16 b
Gas Giant · G-type yellow (Sun-like)
Radius 14.57 R⊕ · 2,929.4 ly
HATS-1 b
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Radius 14.59 R⊕ · 926.2 ly
Kepler-6 b
Gas Giant · G-type yellow (Sun-like)
Radius 14.62 R⊕ · 1,914.7 ly