Key parameters at a glance
- A radius of 0.96 Earth radii
- A mass of 0.84 Earth masses
- Surface gravity around 0.91 g
- An orbital period of 14.425 days
- Semi-major axis 0.1030 AU
- Equilibrium temperature 773 K (500 °C)
- Distance from Earth 2,415.31 light-years
- Earth Similarity Index 0.420
- Travel time at Voyager 1 speed 42,593,916 years
2 siblings around Kepler-399
Kepler-399 b shares its host star with 2 other confirmed planets. Side-by-side measurements below.
| Planet | Type | Radius (R⊕) | Mass (M⊕) | Period (d) | Eq. T (K) | Year |
|---|---|---|---|---|---|---|
| Kepler-399 b this | Rocky Terrestrial | 0.96 | 0.84 | 14.425 | 773 | 2014 |
| Kepler-399 c | Super-Earth | 1.43 | 2.63 | 26.676 | 630 | 2014 |
| Kepler-399 d | Super-Earth | 1.89 | 4.23 | 58.035 | 486 | 2014 |
Kepler-399 b Planet Profile
Physical Specs
Classification
Planet Type
Rocky Terrestrial
Discovery
Size rank in cohort
Rank by radius
#366of 570
top 64.0%
This planet
0.96R⊕
Rocky Terrestrial median
1.01R⊕
Nearest-size peers
| Metric | Earth | Kepler-399 b | Jupiter |
|---|---|---|---|
| Radius (R⊕) | 1.00 | 0.96 | 11.21 |
| Mass (M⊕) | 1.00 | 0.84 | 317.83 |
| Density (g/cm³) | 5.51 | 5.22 | 1.33 |
| Surface Gravity (g) | 1.00 | 0.91 | 2.53 |
| Insolation (S⊕) | 1.00 | 35.63 | 0.037 |
Star Catalogue Identifiers
TIC
TIC 172373693
Gaia DR2
Gaia DR2 2075060264503601280
Gaia DR3
Gaia DR3 2075060264503601280
System
Kepler-399
Percentile among Rocky Terrestrial cohort
Orbit & Habitability
Orbital Dynamics
Year Length
A year here lasts approximately 14.43 Earth days (3.9% of a terrestrial year) on a nearly circular orbit at a mean orbital distance of 0.1030 AU.
Transit Fingerprint
Depth
0.022 %
Duration
3.686 h
Impact parameter b
0.210
Rp / R★
0.013543
Transit midpoint (BJD)
2,454,969.7520
Photometric dip
Transit produces a flux drop of 219 ppm lasting ≈ 3.69 h.
Extended Orbital Architecture
Planet / star radius ratio
0.013543
Semi-major axis / stellar radius
29.750
Impact parameter (b)
0.210
Transit mid-time (BJD)
2,454,969.7520
Angular separation (arcsec)
0.13900
Eq. Temperature
773K
(500 °C)
Insolation (S⊕)
35.63
Earth = 1.00
Earth Similarity (ESI)
0.420
0 = alien, 1 = Earth-identical
Inside the inner HZ boundary (too hot for liquid water) — the surface is too hot to retain surface water.
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-399
Spectral Class
G-type yellow (Sun-like)
Effective Temperature
5,502 K — cooler than the Sun (5,778 K)
Estimated Age
3.98 Gyr — younger than the Sun (4.6 Gyr)
Stellar Radius
0.680 R☉
Stellar Mass
0.902 M☉
Metallicity [Fe/H]
0.14
Extended Stellar Properties
Surface gravity (log g)
4.620 dex
Stellar density
3.030 g/cm³
Metallicity ratio
[Fe/H]
Multi-band Host Photometry — 16 bands
Astrometric Data
Parallax
0.734 mas
Total Proper Motion
9.259 mas/yr
PM Right Ascension
3.26 mas/yr
PM Declination
8.67 mas/yr
Galactic Cartesian (pc)
x = 0.374 · y = -0.660 · z = 0.652
Equatorial (J2000)
RA 299.50172° · Dec 40.67077°
Galactic ℓ, b
75.991° · 5.961°
Ecliptic λ, β
317.151° · 59.375°
HTM-20 index
-725349479
Similar Worlds
Kepler-20 f
Rocky Terrestrial · G-type yellow (Sun-like)
Radius 0.95 R⊕ · 921.6 ly
Kepler-106 d
Rocky Terrestrial · G-type yellow (Sun-like)
Radius 0.95 R⊕ · 1,449.2 ly
Kepler-1297 b
Rocky Terrestrial · G-type yellow (Sun-like)
Radius 0.97 R⊕ · 4,694.9 ly
Kepler-1598 b
Rocky Terrestrial · G-type yellow (Sun-like)
Radius 0.95 R⊕ · 2,021.7 ly
Kepler-271 c
Rocky Terrestrial · G-type yellow (Sun-like)
Radius 0.95 R⊕ · 1,319.4 ly
Kepler-1689 b
Rocky Terrestrial · G-type yellow (Sun-like)
Radius 0.95 R⊕ · 959.3 ly