Key parameters at a glance
- A radius of 2.59 Earth radii
- A mass of 7.22 Earth masses
- Surface gravity around 1.08 g
- An orbital period of 12.285 days
- Semi-major axis 0.0882 AU
- Equilibrium temperature 434 K (161 °C)
- Distance from Earth 1,480.08 light-years
- Earth Similarity Index 0.553
- 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 b 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 | Sub-Neptune | 2.26 | 5.73 | 5.536 | 566 | 2016 |
| Kepler-1388 b this | 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 b Planet Profile
Physical Specs
Classification
Planet Type
Sub-Neptune
Discovery
Size rank in cohort
Rank by radius
#1043of 1978
top 52.7%
This planet
2.59R⊕
Sub-Neptune median
2.71R⊕
Nearest-size peers
| Metric | Earth | Kepler-1388 b | Jupiter |
|---|---|---|---|
| Radius (R⊕) | 1.00 | 2.59 | 11.21 |
| Mass (M⊕) | 1.00 | 7.22 | 317.83 |
| Density (g/cm³) | 5.51 | 2.28 | 1.33 |
| Surface Gravity (g) | 1.00 | 1.08 | 2.53 |
| Insolation (S⊕) | 1.00 | 17.67 | 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 12.29 Earth days (3.4% of a terrestrial year) on a nearly circular orbit at a mean orbital distance of 0.0882 AU.
Transit Fingerprint
Depth
0.162 %
Duration
3.037 h
Impact parameter b
0.015
Rp / R★
0.039013
Transit midpoint (BJD)
2,454,964.9029
Photometric dip
Transit produces a flux drop of 1,617 ppm lasting ≈ 3.04 h.
Extended Orbital Architecture
Planet / star radius ratio
0.039013
Semi-major axis / stellar radius
32.110
Impact parameter (b)
0.015
Transit mid-time (BJD)
2,454,964.9029
Angular separation (arcsec)
0.19400
Eq. Temperature
434K
(161 °C)
Insolation (S⊕)
17.67
Earth = 1.00
Earth Similarity (ESI)
0.553
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.
Detection Signatures
Transit photometry
A transit dip has been observed from at least one telescope.
Transit timing variations
Gravitational interactions from neighbours have been detected.
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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