Key parameters at a glance
- A radius of 0.81 Earth radii
- A mass of 0.46 Earth masses
- Surface gravity around 0.70 g
- An orbital period of 3.173 days
- Semi-major axis 0.0360 AU
- Equilibrium temperature 830 K (557 °C)
- Distance from Earth 1,386.16 light-years
- Earth Similarity Index 0.372
- Travel time at Voyager 1 speed 24,444,983 years
- Almost certainly tidally locked to its host star given the close orbit
1 sibling around Kepler-388
Kepler-388 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 |
|---|---|---|---|---|---|---|
| Kepler-388 b this | Rocky Terrestrial | 0.81 | 0.46 | 3.173 | 830 | 2014 |
| Kepler-388 c | Rocky Terrestrial | 0.86 | 0.57 | 13.297 | 515 | 2014 |
Kepler-388 b Planet Profile
Physical Specs
Classification
Planet Type
Rocky Terrestrial
Discovery
Size rank in cohort
Rank by radius
#474of 570
top 83.0%
This planet
0.81R⊕
Rocky Terrestrial median
1.01R⊕
Nearest-size peers
| Metric | Earth | Kepler-388 b | Jupiter |
|---|---|---|---|
| Radius (R⊕) | 1.00 | 0.81 | 11.21 |
| Mass (M⊕) | 1.00 | 0.46 | 317.83 |
| Density (g/cm³) | 5.51 | 4.73 | 1.33 |
| Surface Gravity (g) | 1.00 | 0.70 | 2.53 |
| Insolation (S⊕) | 1.00 | 112.21 | 0.037 |
Star Catalogue Identifiers
TIC
TIC 164786156
Gaia DR2
Gaia DR2 2106711424679833984
Gaia DR3
Gaia DR3 2106711424679833984
System
Kepler-388
Percentile among Rocky Terrestrial cohort
Orbit & Habitability
Orbital Dynamics
Year Length
A year here lasts approximately 3.17 Earth days (0.9% of a terrestrial year) on a nearly circular orbit at a mean orbital distance of 0.0360 AU.
Transit Fingerprint
Depth
0.020 %
Duration
2.042 h
Impact parameter b
0.200
Rp / R★
0.013094
Transit midpoint (BJD)
2,454,966.6997
Photometric dip
Transit produces a flux drop of 205 ppm lasting ≈ 2.04 h.
Extended Orbital Architecture
Planet / star radius ratio
0.013094
Semi-major axis / stellar radius
12.830
Impact parameter (b)
0.200
Transit mid-time (BJD)
2,454,966.6997
Angular separation (arcsec)
0.08470
Eq. Temperature
830K
(557 °C)
Insolation (S⊕)
112.21
Earth = 1.00
Earth Similarity (ESI)
0.372
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
Rowe et al. 2014Instrument
Kepler CCD Array
Publication
2014-03
Observation locale
Space
Discovery cohort
Planets confirmed in 2014 at Kepler (12 shown).
Host System: Kepler-388
Spectral Class
K-type orange
Effective Temperature
4,498 K — cooler than the Sun (5,778 K)
Estimated Age
13.90 Gyr — older than the Sun (4.6 Gyr)
Stellar Radius
0.586 R☉
Stellar Mass
0.635 M☉
Metallicity [Fe/H]
0.00
Extended Stellar Properties
Surface gravity (log g)
4.690 dex
Stellar density
3.169 g/cm³
Metallicity ratio
[Fe/H]
Multi-band Host Photometry — 16 bands
Astrometric Data
Parallax
1.636 mas
Total Proper Motion
19.234 mas/yr
PM Right Ascension
0.42 mas/yr
PM Declination
-19.23 mas/yr
Galactic Cartesian (pc)
x = 0.182 · y = -0.688 · z = 0.702
Equatorial (J2000)
RA 284.82806° · Dec 44.60865°
Galactic ℓ, b
74.732° · 17.365°
Ecliptic λ, β
297.357° · 66.645°
HTM-20 index
1004160293
Similar Worlds
Kepler-220 b
Rocky Terrestrial · K-type orange
Radius 0.81 R⊕ · 558.1 ly
HD 23472 e
Rocky Terrestrial · K-type orange
Radius 0.82 R⊕ · 127.3 ly
Kepler-1076 b
Rocky Terrestrial · K-type orange
Radius 0.80 R⊕ · 649.1 ly
Kepler-1446 b
Rocky Terrestrial · K-type orange
Radius 0.82 R⊕ · 496.0 ly
Kepler-390 b
Rocky Terrestrial · K-type orange
Radius 0.82 R⊕ · 1,419.7 ly
Kepler-390 c
Rocky Terrestrial · K-type orange
Radius 0.79 R⊕ · 1,419.7 ly