Key parameters at a glance
- A radius of 0.94 Earth radii
- A mass of 1.14 Earth masses
- Surface gravity around 1.30 g
- An orbital period of 0.365 days
- Semi-major axis 0.0096 AU
- Equilibrium temperature 2,432 K (2159 °C)
- Distance from Earth 973.16 light-years
- Earth Similarity Index 0.108
- Travel time at Voyager 1 speed 17,161,701 years
2 siblings around K2-157
K2-157 b shares its host star with 2 other confirmed planets. Side-by-side measurements below.
K2-157 b Planet Profile
Physical Specs
Classification
Planet Type
Rocky Terrestrial
Discovery
Size rank in cohort
Rank by radius
#389of 570
top 68.1%
This planet
0.94R⊕
Rocky Terrestrial median
1.01R⊕
Nearest-size peers
| Metric | Earth | K2-157 b | Jupiter |
|---|---|---|---|
| Radius (R⊕) | 1.00 | 0.94 | 11.21 |
| Mass (M⊕) | 1.00 | 1.14 | 317.83 |
| Density (g/cm³) | 5.51 | 7.70 | 1.33 |
| Surface Gravity (g) | 1.00 | 1.30 | 2.53 |
| Insolation (S⊕) | 1.00 | 6,660.00 | 0.037 |
Alternative Mass Estimates
| Method | Value | Interpretation |
|---|---|---|
| Best measured mass | 1.140 M⊕ | Direct mass measurement (not derived). |
Star Catalogue Identifiers
TIC
TIC 349445372
Gaia DR2
Gaia DR2 3596333042162818304
Gaia DR3
Gaia DR3 3596333042162818304
System
K2-157
Percentile among Rocky Terrestrial cohort
Orbit & Habitability
Orbital Dynamics
Year Length
A year here lasts roughly 8.8 hours long at a mean orbital distance of 0.0096 AU.
Transit Fingerprint
Depth
0.010 %
Duration
1.161 h
Impact parameter b
0.030
Rp / R★
0.009960
Transit midpoint (BJD)
2,457,582.8220
Photometric dip
Transit produces a flux drop of 99 ppm lasting ≈ 1.16 h.
Extended Orbital Architecture
Planet / star radius ratio
0.009960
Semi-major axis / stellar radius
2.405
Impact parameter (b)
0.030
RV semi-amplitude (K)
1.100 m/s
Transit mid-time (BJD)
2,457,582.8220
Angular separation (arcsec)
0.03220
Eq. Temperature
2,432K
(2159 °C)
Insolation (S⊕)
6,660.00
Earth = 1.00
Earth Similarity (ESI)
0.108
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
Mayo et al. 2018Instrument
Kepler CCD Array
Publication
2018-03
Observation locale
Space
Discovery cohort
Planets confirmed in 2018 at K2 (12 shown).
Host System: K2-157
Spectral Class
G-type yellow (Sun-like)
Effective Temperature
5,334 K — cooler than the Sun (5,778 K)
Estimated Age
8.80 Gyr — older than the Sun (4.6 Gyr)
Stellar Radius
0.860 R☉
Stellar Mass
0.890 M☉
Metallicity [Fe/H]
0.02
Extended Stellar Properties
Surface gravity (log g)
4.450 dex
Stellar density
1.679 g/cm³
Systemic radial velocity
43.45 km/s
Rotational v·sin i
3.00 km/s
Activity index (log R'HK)
-5.077
Metallicity ratio
[Fe/H]
Multi-band Host Photometry — 12 bands
Astrometric Data
Parallax
3.324 mas
Total Proper Motion
37.511 mas/yr
PM Right Ascension
36.72 mas/yr
PM Declination
-7.65 mas/yr
Galactic Cartesian (pc)
x = -0.993 · y = -0.065 · z = -0.101
Equatorial (J2000)
RA 183.75150° · Dec -5.78202°
Galactic ℓ, b
286.604° · 55.930°
Ecliptic λ, β
185.736° · -3.815°
HTM-20 index
1503740923
Similar Worlds
Kepler-1898 b
Rocky Terrestrial · G-type yellow (Sun-like)
Radius 0.93 R⊕ · 1,177.2 ly
Kepler-1505 b
Rocky Terrestrial · G-type yellow (Sun-like)
Radius 0.93 R⊕ · 1,615.0 ly
Kepler-1572 b
Rocky Terrestrial · G-type yellow (Sun-like)
Radius 0.94 R⊕ · 3,087.4 ly
Kepler-1438 b
Rocky Terrestrial · G-type yellow (Sun-like)
Radius 0.94 R⊕ · 3,764.3 ly
Kepler-1425 b
Rocky Terrestrial · G-type yellow (Sun-like)
Radius 0.94 R⊕ · 2,817.6 ly
Kepler-1689 b
Rocky Terrestrial · G-type yellow (Sun-like)
Radius 0.95 R⊕ · 959.3 ly