Key parameters at a glance
- A radius of 2.26 Earth radii
- A mass of 5.73 Earth masses
- Surface gravity around 1.12 g
- An orbital period of 5.536 days
- Semi-major axis 0.0519 AU
- Equilibrium temperature 566 K (293 °C)
- Distance from Earth 1,480.08 light-years
- Earth Similarity Index 0.461
- Travel time at Voyager 1 speed 26,101,203 years
- Almost certainly tidally locked to its host star given the close orbit
3 siblings around Kepler-1388
Kepler-1388 c shares its host star with 3 other confirmed planets. Side-by-side measurements below.
| Planet | Type | Radius (R⊕) | Mass (M⊕) | Period (d) | Eq. T (K) | Year |
|---|---|---|---|---|---|---|
| Kepler-1388 c this | Sub-Neptune | 2.26 | 5.73 | 5.536 | 566 | 2016 |
| Kepler-1388 b | Sub-Neptune | 2.59 | 7.22 | 12.285 | 434 | 2016 |
| Kepler-1388 d | Sub-Neptune | 2.86 | 8.55 | 20.957 | 363 | 2016 |
| Kepler-1388 e | Sub-Neptune | 2.46 | 6.62 | 37.633 | 299 | 2016 |
Kepler-1388 c Planet Profile
Physical Specs
Classification
Planet Type
Sub-Neptune
Discovery
Size rank in cohort
Rank by radius
#1572of 1978
top 79.4%
This planet
2.26R⊕
Sub-Neptune median
2.71R⊕
Nearest-size peers
| Metric | Earth | Kepler-1388 c | Jupiter |
|---|---|---|---|
| Radius (R⊕) | 1.00 | 2.26 | 11.21 |
| Mass (M⊕) | 1.00 | 5.73 | 317.83 |
| Density (g/cm³) | 5.51 | 2.73 | 1.33 |
| Surface Gravity (g) | 1.00 | 1.12 | 2.53 |
| Insolation (S⊕) | 1.00 | 51.04 | 0.037 |
Star Catalogue Identifiers
TIC
TIC 164524311
Gaia DR2
Gaia DR2 2107617246162706048
Gaia DR3
Gaia DR3 2107617246162706048
System
Kepler-1388
Percentile among Sub-Neptune cohort
Orbit & Habitability
Orbital Dynamics
Year Length
A year here lasts approximately 5.54 Earth days (1.5% of a terrestrial year) on a nearly circular orbit at a mean orbital distance of 0.0519 AU.
Transit Fingerprint
Depth
0.122 %
Duration
2.182 h
Impact parameter b
0.167
Rp / R★
0.034296
Transit midpoint (BJD)
2,454,964.8857
Photometric dip
Transit produces a flux drop of 1,223 ppm lasting ≈ 2.18 h.
Extended Orbital Architecture
Planet / star radius ratio
0.034296
Semi-major axis / stellar radius
19.800
Impact parameter (b)
0.167
Transit mid-time (BJD)
2,454,964.8857
Angular separation (arcsec)
0.11400
Eq. Temperature
566K
(293 °C)
Insolation (S⊕)
51.04
Earth = 1.00
Earth Similarity (ESI)
0.461
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
Morton et al. 2016Instrument
Kepler CCD Array
Publication
2016-05
Observation locale
Space
Discovery cohort
Planets confirmed in 2016 at Kepler (12 shown).
Host System: Kepler-1388
Spectral Class
K-type orange
Effective Temperature
4,098 K — cooler than the Sun (5,778 K)
Estimated Age
4.47 Gyr — younger than the Sun (4.6 Gyr)
Stellar Radius
0.610 R☉
Stellar Mass
0.630 M☉
Metallicity [Fe/H]
0.02
Extended Stellar Properties
Surface gravity (log g)
4.670 dex
Stellar density
3.828 g/cm³
Metallicity ratio
[Fe/H]
Multi-band Host Photometry — 16 bands
Astrometric Data
Parallax
2.175 mas
Total Proper Motion
16.932 mas/yr
PM Right Ascension
-7.32 mas/yr
PM Declination
-15.27 mas/yr
Galactic Cartesian (pc)
x = 0.157 · y = -0.661 · z = 0.733
Equatorial (J2000)
RA 283.33602° · Dec 47.17445°
Galactic ℓ, b
76.884° · 19.232°
Ecliptic λ, β
296.450° · 69.392°
HTM-20 index
1364629176
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