Key parameters at a glance
- A radius of 1.54 Earth radii
- A mass of 7.30 Earth masses
- Surface gravity around 3.08 g
- An orbital period of 4.016 days
- Semi-major axis 0.0499 AU
- Equilibrium temperature 1,266 K (993 °C)
- Distance from Earth 628.47 light-years
- Earth Similarity Index 0.200
- Travel time at Voyager 1 speed 11,083,068 years
1 sibling around K2-38
K2-38 b shares its host star with 1 other confirmed planet. Side-by-side measurements below.
| Planet | Type | Radius (R⊕) | Mass (M⊕) | Period (d) | Eq. T (K) | Year |
|---|---|---|---|---|---|---|
| K2-38 b this | Super-Earth | 1.54 | 7.30 | 4.016 | 1,266 | 2016 |
| K2-38 c | Sub-Neptune | 2.29 | 8.30 | 10.561 | 916 | 2016 |
K2-38 b Planet Profile
Physical Specs
Classification
Planet Type
Super-Earth
Discovery
Size rank in cohort
Rank by radius
#670of 1176
top 56.9%
This planet
1.54R⊕
Super-Earth median
1.60R⊕
Nearest-size peers
| Metric | Earth | K2-38 b | Jupiter |
|---|---|---|---|
| Radius (R⊕) | 1.00 | 1.54 | 11.21 |
| Mass (M⊕) | 1.00 | 7.30 | 317.83 |
| Density (g/cm³) | 5.51 | 11.00 | 1.33 |
| Surface Gravity (g) | 1.00 | 3.08 | 2.53 |
| Insolation (S⊕) | 1.00 | 426.00 | 0.037 |
Alternative Mass Estimates
| Method | Value | Interpretation |
|---|---|---|
| Best measured mass | 7.300 M⊕ | Direct mass measurement (not derived). |
Star Catalogue Identifiers
TIC
TIC 12666215
Gaia DR2
Gaia DR2 6237129658760381056
Gaia DR3
Gaia DR3 6237129658760381056
System
K2-38
Percentile among Super-Earth cohort
Orbit & Habitability
Orbital Dynamics
Year Length
A year here lasts approximately 4.02 Earth days (1.1% of a terrestrial year) on a mildly elliptical path at a mean orbital distance of 0.0499 AU.
Transit Fingerprint
Depth
0.026 %
Duration
2.740 h
Impact parameter b
0.480
Rp / R★
0.013300
Transit midpoint (BJD)
2,456,896.8786
Photometric dip
Transit produces a flux drop of 261 ppm lasting ≈ 2.74 h.
Extended Orbital Architecture
Planet / star radius ratio
0.013300
Semi-major axis / stellar radius
10.130
Impact parameter (b)
0.480
RV semi-amplitude (K)
2.950 m/s
Transit mid-time (BJD)
2,456,896.8786
Long. of periastron (ω)
16.00°
Angular separation (arcsec)
0.25900
Eq. Temperature
1,266K
(993 °C)
Insolation (S⊕)
426.00
Earth = 1.00
Earth Similarity (ESI)
0.200
0 = alien, 1 = Earth-identical
Inside the inner HZ boundary (too hot for liquid water) — 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
Sinukoff et al. 2016Instrument
Kepler CCD Array
Publication
2016-08
Observation locale
Space
Discovery cohort
Planets confirmed in 2016 at K2 (12 shown).
Host System: K2-38
Spectral Class
G-type yellow (Sun-like)
Effective Temperature
5,731 K — cooler than the Sun (5,778 K)
Estimated Age
6.70 Gyr — older than the Sun (4.6 Gyr)
Stellar Radius
1.060 R☉
Stellar Mass
1.030 M☉
Metallicity [Fe/H]
0.26
Extended Stellar Properties
Surface gravity (log g)
4.380 dex
Stellar density
1.210 g/cm³
Systemic radial velocity
-35.33 km/s
Rotational v·sin i
2.00 km/s
Activity index (log R'HK)
-5.060
Metallicity ratio
[Fe/H]
Multi-band Host Photometry — 12 bands
Astrometric Data
Parallax
5.162 mas
Total Proper Motion
68.273 mas/yr
PM Right Ascension
-56.97 mas/yr
PM Declination
-37.63 mas/yr
Galactic Cartesian (pc)
x = -0.459 · y = -0.796 · z = -0.394
Equatorial (J2000)
RA 240.03331° · Dec -23.18942°
Galactic ℓ, b
349.629° · 22.121°
Ecliptic λ, β
242.635° · -2.552°
HTM-20 index
682796070
Similar Worlds
Kepler-1287 b
Super-Earth · G-type yellow (Sun-like)
Radius 1.54 R⊕ · 3,272.2 ly
Kepler-337 b
Super-Earth · G-type yellow (Sun-like)
Radius 1.54 R⊕ · 2,211.3 ly
K2-350 b
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TOI-512 b
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K2-226 b
Super-Earth · G-type yellow (Sun-like)
Radius 1.54 R⊕ · 689.1 ly